YouTube 超快聊天

YouTube直播聊天的终极性能提升

当前为 2023-07-25 提交的版本,查看 最新版本

// ==UserScript==
// @name                YouTube Super Fast Chat
// @version             0.20.0
// @license             MIT
// @name:ja             YouTube スーパーファーストチャット
// @name:zh-TW          YouTube 超快聊天
// @name:zh-CN          YouTube 超快聊天
// @icon                https://github.com/cyfung1031/userscript-supports/raw/main/icons/super-fast-chat.png
// @namespace           UserScript
// @match               https://www.youtube.com/live_chat*
// @match               https://www.youtube.com/live_chat_replay*
// @author              CY Fung
// @require             https://gf.qytechs.cn/scripts/465819-api-for-customelements-in-youtube/code/API%20for%20CustomElements%20in%20YouTube.js?version=1215280
// @run-at              document-start
// @grant               none
// @unwrap
// @allFrames           true
// @inject-into         page
//
// @compatible          firefox Violentmonkey
// @compatible          firefox Tampermonkey
// @compatible          firefox FireMonkey
// @compatible          chrome Violentmonkey
// @compatible          chrome Tampermonkey
// @compatible          opera Violentmonkey
// @compatible          opera Tampermonkey
// @compatible          safari Stay
// @compatible          edge Violentmonkey
// @compatible          edge Tampermonkey
// @compatible          brave Violentmonkey
// @compatible          brave Tampermonkey
//
// @description         Ultimate Performance Boost for YouTube Live Chats
// @description:ja      YouTubeのライブチャットの究極のパフォーマンスブースト
// @description:zh-TW   YouTube直播聊天的終極性能提升
// @description:zh-CN   YouTube直播聊天的终极性能提升
//
// ==/UserScript==

((__CONTEXT__) => {
  'use strict';

  const ENABLE_REDUCED_MAXITEMS_FOR_FLUSH = true;         // TRUE to enable trimming down to 25 messages when there are too many unrendered messages
  const MAX_ITEMS_FOR_TOTAL_DISPLAY = 90;                 // By default, 250 latest messages will be displayed, but displaying 90 messages is already sufficient.
  const MAX_ITEMS_FOR_FULL_FLUSH = 25;                    // If there are too many new (stacked) messages not yet rendered, clean all and flush 25 latest messages then incrementally added back to 90 messages

  const ENABLE_NO_SMOOTH_TRANSFORM = true;                // Depends on whether you want the animation effect for new chat messages
  const USE_OPTIMIZED_ON_SCROLL_ITEMS = true;             // TRUE for the majority
  const USE_WILL_CHANGE_CONTROLLER = false;               // FALSE for the majority
  const ENABLE_FULL_RENDER_REQUIRED_PREFERRED = true;     // In Chrome, the rendering of new chat messages could be too fast for no smooth transform. 80ms delay of displaying new messages should be sufficient for element rendering.
  const ENABLE_OVERFLOW_ANCHOR_PREFERRED = true;          // Enable `overflow-anchor: auto` to lock the scroll list at the bottom for no smooth transform.

  const FIX_SHOW_MORE_BUTTON_LOCATION = true;             // When there are voting options (bottom panel), move the "show more" button to the top.
  const FIX_INPUT_PANEL_OVERFLOW_ISSUE = true;            // When the super chat button is flicking with color, the scrollbar might come out.
  const FIX_INPUT_PANEL_BORDER_ISSUE = true;              // No border should be allowed if there is an empty input panel.
  const SET_CONTAIN_FOR_CHATROOM = true;                  // Rendering hacks (`contain`) for chatroom elements. [ General ]

  const FORCE_CONTENT_VISIBILITY_UNSET = true;            // Content-visibility should be always VISIBLE for high performance and great rendering.
  const FORCE_WILL_CHANGE_UNSET = true;                   // Will-change should be always UNSET (auto) for high performance and low energy impact.

  // Replace requestAnimationFrame timers with custom implementation
  const ENABLE_RAF_HACK_TICKERS = true;         // When there is a ticker
  const ENABLE_RAF_HACK_DOCKED_MESSAGE = true;  // To be confirmed
  const ENABLE_RAF_HACK_INPUT_RENDERER = true;  // To be confirmed
  const ENABLE_RAF_HACK_EMOJI_PICKER = true;    // When changing the page of the emoji picker

  // Force rendering all the character subsets of the designated font(s) before messages come (Pre-Rendering of Text)
  const ENABLE_FONT_PRE_RENDERING_PREFERRED = 1 | 2 | 4 | 8 | 16;

  // Backdrop `filter: blur(4px)` inside the iframe can extend to the whole page, causing a negative visual impact on the video you are watching.
  const NO_BACKDROP_FILTER_WHEN_MENU_SHOWN = true;

  // Data Manipulation for Participants (Participant List)
  const DO_PARTICIPANT_LIST_HACKS = true;                     // TRUE for the majority
  const SHOW_PARTICIPANT_CHANGES_IN_CONSOLE = false;          // Just too annoying to show them all in popular chat
  const CHECK_CHANGE_TO_PARTICIPANT_RENDERER_CONTENT = true;  // Only consider changes in renderable content (not concerned with the last chat message of the participants)


  const { IntersectionObserver } = __CONTEXT__;

  /** @type {globalThis.PromiseConstructor} */
  const Promise = (async () => { })().constructor; // YouTube hacks Promise in WaterFox Classic and "Promise.resolve(0)" nevers resolve.

  if (!IntersectionObserver) return console.warn("Your browser does not support IntersectionObserver.\nPlease upgrade to the latest version.")

  if (!customYtElements) return console.error("library 'customYtElements' is required.")


  // necessity of cssText3_smooth_transform_position to be checked.
  const cssText3_smooth_transform_position = ENABLE_NO_SMOOTH_TRANSFORM ? `

    #item-offset.style-scope.yt-live-chat-item-list-renderer > #items.style-scope.yt-live-chat-item-list-renderer {
        position: static !important;
    }

  `: '';

  // fallback if dummy style fn fails
  const cssText4_smooth_transform_forced_props = ENABLE_NO_SMOOTH_TRANSFORM ? `

    /* optional */
    #item-offset.style-scope.yt-live-chat-item-list-renderer {
        height: auto !important;
        min-height: unset !important;
    }

    #items.style-scope.yt-live-chat-item-list-renderer {
        transform: translateY(0px) !important;
    }

    /* optional */

  `: '';

  const cssText5 = SET_CONTAIN_FOR_CHATROOM ? `

    /* ------------------------------------------------------------------------------------------------------------- */

    yt-live-chat-author-chip #chat-badges.yt-live-chat-author-chip, yt-live-chat-author-chip #chat-badges.yt-live-chat-author-chip yt-live-chat-author-badge-renderer, yt-live-chat-author-chip #chat-badges.yt-live-chat-author-chip yt-live-chat-author-badge-renderer #image, yt-live-chat-author-chip #chat-badges.yt-live-chat-author-chip yt-live-chat-author-badge-renderer #image img {
        contain: layout style;
    }

    #items.style-scope.yt-live-chat-item-list-renderer {
        contain: layout paint style;
    }

    #item-offset.style-scope.yt-live-chat-item-list-renderer {
        contain: style;
    }

    #item-scroller.style-scope.yt-live-chat-item-list-renderer {
        contain: size style;
    }

    #contents.style-scope.yt-live-chat-item-list-renderer, #chat.style-scope.yt-live-chat-renderer, img.style-scope.yt-img-shadow[width][height] {
        contain: size layout paint style;
    }

    .style-scope.yt-live-chat-ticker-renderer[role="button"][aria-label], .style-scope.yt-live-chat-ticker-renderer[role="button"][aria-label] > #container {
        contain: layout paint style;
    }

    yt-live-chat-text-message-renderer.style-scope.yt-live-chat-item-list-renderer, yt-live-chat-membership-item-renderer.style-scope.yt-live-chat-item-list-renderer, yt-live-chat-paid-message-renderer.style-scope.yt-live-chat-item-list-renderer, yt-live-chat-banner-manager.style-scope.yt-live-chat-item-list-renderer {
        contain: layout style;
    }

    tp-yt-paper-tooltip[style*="inset"][role="tooltip"] {
        contain: layout paint style;
    }

    /* ------------------------------------------------------------------------------------------------------------- */

  ` : '';

  const cssText6b_show_more_button = FIX_SHOW_MORE_BUTTON_LOCATION ? `

    yt-live-chat-renderer[has-action-panel-renderer] #show-more.yt-live-chat-item-list-renderer{
        top: 4px;
        transition-property: top;
        bottom: unset;
    }

    yt-live-chat-renderer[has-action-panel-renderer] #show-more.yt-live-chat-item-list-renderer[disabled]{
        top: -42px;
    }

  `: '';

  const cssText6c_input_panel_overflow = FIX_INPUT_PANEL_OVERFLOW_ISSUE ? `

    #input-panel #picker-buttons yt-live-chat-icon-toggle-button-renderer#product-picker {
        contain: layout style;
    }

    #chat.yt-live-chat-renderer ~ #panel-pages.yt-live-chat-renderer {
        overflow: visible;
    }

  `: '';

  const cssText6d_input_panel_border = FIX_INPUT_PANEL_BORDER_ISSUE ? `

    html #panel-pages.yt-live-chat-renderer > #input-panel.yt-live-chat-renderer:not(:empty) {
        --yt-live-chat-action-panel-top-border: none;
    }

    html #panel-pages.yt-live-chat-renderer > #input-panel.yt-live-chat-renderer.iron-selected > *:first-child {
        border-top: 1px solid var(--yt-live-chat-panel-pages-border-color);
    }

    html #panel-pages.yt-live-chat-renderer {
        border-top: 0;
        border-bottom: 0;
    }

  `: '';

  const cssText7b_content_visibility_unset = FORCE_CONTENT_VISIBILITY_UNSET ? `

    img,
    yt-img-shadow[height][width],
    yt-img-shadow {
        content-visibility: visible !important;
    }

  `  : '';

  const cssText7c_will_change_unset = FORCE_WILL_CHANGE_UNSET ? `

    /* remove YouTube constant will-change */
    /* constant value will slow down the performance; default auto */

    /* www-player.css */
    html .ytp-contextmenu,
    html .ytp-settings-menu {
        will-change: unset;
    }

    /* frequently matched elements */
    html .fill.yt-interaction,
    html .stroke.yt-interaction,
    html .yt-spec-touch-feedback-shape__fill,
    html .yt-spec-touch-feedback-shape__stroke {
        will-change: unset;
    }

    /* live_chat_polymer.js */
    /*
    html .toggle-button.tp-yt-paper-toggle-button,
    html #primaryProgress.tp-yt-paper-progress,
    html #secondaryProgress.tp-yt-paper-progress,
    html #onRadio.tp-yt-paper-radio-button,
    html .fill.yt-interaction,
    html .stroke.yt-interaction,
    html .yt-spec-touch-feedback-shape__fill,
    html .yt-spec-touch-feedback-shape__stroke {
        will-change: unset;
    }
    */

    /* desktop_polymer_enable_wil_icons.js */
    /* html .fill.yt-interaction,
    html .stroke.yt-interaction, */
    html tp-yt-app-header::before,
    html tp-yt-iron-list,
    html #items.tp-yt-iron-list > *,
    html #onRadio.tp-yt-paper-radio-button,
    html .toggle-button.tp-yt-paper-toggle-button,
    html ytd-thumbnail-overlay-toggle-button-renderer[use-expandable-tooltip] #label.ytd-thumbnail-overlay-toggle-button-renderer,
    html #items.ytd-post-multi-image-renderer,
    html #items.ytd-horizontal-card-list-renderer,
    html #items.yt-horizontal-list-renderer,
    html #left-arrow.yt-horizontal-list-renderer,
    html #right-arrow.yt-horizontal-list-renderer,
    html #items.ytd-video-description-infocards-section-renderer,
    html #items.ytd-video-description-music-section-renderer,
    html #chips.ytd-feed-filter-chip-bar-renderer,
    html #chips.yt-chip-cloud-renderer,
    html #items.ytd-merch-shelf-renderer,
    html #items.ytd-product-details-image-carousel-renderer,
    html ytd-video-preview,
    html #player-container.ytd-video-preview,
    html #primaryProgress.tp-yt-paper-progress,
    html #secondaryProgress.tp-yt-paper-progress,
    html ytd-miniplayer[enabled] /* ,
    html .yt-spec-touch-feedback-shape__fill,
    html .yt-spec-touch-feedback-shape__stroke */ {
        will-change: unset;
    }

    /* other */
    .ytp-videowall-still-info-content[class],
    .ytp-suggestion-image[class] {
        will-change: unset !important;
    }

  ` : '';

  const ENABLE_FONT_PRE_RENDERING = typeof HTMLElement.prototype.append === 'function' ? (ENABLE_FONT_PRE_RENDERING_PREFERRED || 0) : 0;
  const cssText8_fonts_pre_render = ENABLE_FONT_PRE_RENDERING ? `

    elzm-fonts {
        visibility: collapse;
        position: fixed;
        top: -10px;
        left: -10px;
        font-size: 10pt;
        line-height: 100%;
        width: 100px;
        height: 100px;
        transform: scale(0.1);
        transform: scale(0.01);
        transform: scale(0.001);
        transform-origin: 0 0;
        contain: strict;
        display: block;

        user-select: none !important;
        pointer-events: none !important;
    }

    elzm-fonts[id]#elzm-fonts-yk75g {
        user-select: none !important;
        pointer-events: none !important;
    }

    elzm-font {
        visibility: collapse;
        position: absolute;
        line-height: 100%;
        width: 100px;
        height: 100px;
        contain: strict;
        display: block;

        user-select: none !important;
        pointer-events: none !important;
    }

    elzm-font::before {
        visibility: collapse;
        position: absolute;
        line-height: 100%;
        width: 100px;
        height: 100px;
        contain: strict;
        display: block;

        content: '0aZ!@#$~^&*()_-+[]{}|;:><?\\0460\\0301\\0900\\1F00\\0370\\0102\\0100\\28EB2\\28189\\26DA0\\25A9C\\249BB\\23F61\\22E8B\\21927\\21076\\2048E\\1F6F5\\FF37\\F94F\\F0B2\\9F27\\9D9A\\9BEA\\9A6B\\98EC\\9798\\9602\\949D\\9370\\926B\\913A\\8FA9\\8E39\\8CC1\\8B26\\8983\\8804\\8696\\8511\\83BC\\828D\\8115\\7F9A\\7E5B\\7D07\\7B91\\7A2C\\78D2\\776C\\7601\\74AA\\73B9\\7265\\70FE\\6FBC\\6E88\\6D64\\6C3F\\6A9C\\6957\\67FE\\66B3\\6535\\63F2\\628E\\612F\\5FE7\\5E6C\\5CEE\\5B6D\\5A33\\58BC\\575B\\5611\\54BF\\536E\\51D0\\505D\\4F22\\4AD1\\41DB\\3B95\\3572\\2F3F\\26FD\\25A1\\2477\\208D\\1D0A\\1FB\\A1\\A3\\B4\\2CB\\60\\10C\\E22\\A5\\4E08\\B0\\627\\2500\\5E\\201C\\3C\\B7\\23\\26\\3E\\D\\20\\25EE8\\1F235\\FFD7\\FA10\\F92D\\9E8B\\9C3E\\9AE5\\98EB\\971D\\944A\\92BC\\9143\\8F52\\8DC0\\8B2D\\8973\\87E2\\8655\\84B4\\82E8\\814A\\7F77\\7D57\\7BC8\\7A17\\7851\\768C\\7511\\736C\\7166\\6F58\\6D7C\\6B85\\69DD\\6855\\667E\\64D2\\62CF\\6117\\5F6C\\5D9B\\5BBC\\598B\\57B3\\5616\\543F\\528D\\50DD\\4F57\\4093\\3395\\32B5\\31C8\\3028\\2F14\\25E4\\24D1\\2105\\2227\\A8\\2D9\\2CA\\2467\\B1\\2020\\2466\\251C\\266B\\AF\\4E91\\221E\\2464\\2266\\2207\\4E32\\25B3\\2463\\2010\\2103\\3014\\25C7\\24\\25BD\\4E18\\2460\\21D2\\2015\\2193\\4E03\\7E\\25CB\\2191\\25BC\\3D\\500D\\4E01\\25\\30F6\\2605\\266A\\40\\2B\\4E16\\7C\\A9\\4E\\21\\1F1E9\\FEE3\\F0A7\\9F3D\\9DFA\\9C3B\\9A5F\\98C8\\972A\\95B9\\94E7\\9410\\92B7\\914C\\8FE2\\8E2D\\8CAF\\8B5E\\8A02\\8869\\86E4\\8532\\83B4\\82A9\\814D\\7FFA\\7ED7\\7DC4\\7CCC\\7BC3\\7ACA\\797C\\783E\\770F\\760A\\74EF\\73E7\\72DD\\719C\\7005\\6ED8\\6DC3\\6CB2\\6A01\\68E1\\6792\\663A\\64F8\\63BC\\623B\\60FA\\5FD1\\5EA3\\5D32\\5BF5\\5AB2\\5981\\5831\\570A\\5605\\5519\\53FB\\52A2\\5110\\4FE3\\4EB8\\3127\\279C\\2650\\254B\\23E9\\207B\\1D34\\2AE\\176\\221A\\161\\200B\\300C\\4E4C\\1F921\\FF78\\FA0A\\F78A\\9EB9\\9D34\\9BD3\\9A6F\\9912\\97C6\\964E\\950C\\93E4\\92E5\\91F0\\90BB\\8F68\\8E18\\8B6C\\89F6\\889B\\874C\\8602\\84B1\\8378\\826E\\8113\\7FB1\\7EAF\\7D89\\7C20\\7AFB\\7988\\7840\\7705\\75CC\\749A\\73B3\\727F\\7113\\6FE8\\6ED6\\6DD3\\6CDA\\6BBB\\6A31\\6900\\67D9\\66A7\\655D\\6427\\630D\\61C6\\60AC\\5F78\\5E34\\5CE0\\5B80\\5A51\\590B\\57A1\\566F\\5551\\543D\\52DB\\518F\\5032\\3A17\\305C\\2749\\264A\\2567\\2476\\2139\\1EC0\\11AF\\2C8\\1AF\\E17\\2190\\2022\\2502\\2312\\2025\\50';

        user-select: none !important;
        pointer-events: none !important;
    }

  `: '';

  const cssText9_no_backdrop_filter_when_menu_shown = NO_BACKDROP_FILTER_WHEN_MENU_SHOWN ? `
    tp-yt-iron-dropdown.yt-live-chat-app ytd-menu-popup-renderer  {
        -webkit-backdrop-filter: none;
        backdrop-filter: none;
    }
  `: '';


  const addCss = () => `

  ${cssText8_fonts_pre_render}

  ${cssText9_no_backdrop_filter_when_menu_shown}

  @supports (contain: layout paint style) {

    ${cssText5}

  }

  @supports (color: var(--general)) {

    html {
        --yt-live-chat-item-list-renderer-padding: 0px 0px;
    }

    ${cssText3_smooth_transform_position}

    ${cssText7c_will_change_unset}

    ${cssText7b_content_visibility_unset}

    yt-live-chat-item-list-renderer:not([allow-scroll]) #item-scroller.yt-live-chat-item-list-renderer {
        overflow-y: scroll;
        padding-right: 0;
    }

    ${cssText4_smooth_transform_forced_props}

    yt-icon[icon="down_arrow"] > *, yt-icon-button#show-more > * {
        pointer-events: none !important;
    }

    #continuations, #continuations * {
        contain: strict;
        position: fixed;
        top: 2px;
        height: 1px;
        width: 2px;
        height: 1px;
        visibility: collapse;
    }

    ${cssText6b_show_more_button}

    ${cssText6d_input_panel_border}

    ${cssText6c_input_panel_overflow}

  }


  @supports (overflow-anchor: auto) {

    .no-anchor * {
        overflow-anchor: none;
    }
    .no-anchor > item-anchor {
        overflow-anchor: auto;
    }

    item-anchor {

        height:1px;
        width: 100%;
        transform: scaleY(0.00001);
        transform-origin:0 0;
        contain: strict;
        opacity:0;
        display:flex;
        position:relative;
        flex-shrink:0;
        flex-grow:0;
        margin-bottom:0;
        overflow:hidden;
        box-sizing:border-box;
        visibility: visible;
        content-visibility: visible;
        contain-intrinsic-size: auto 1px;
        pointer-events:none !important;

    }

    #item-scroller.style-scope.yt-live-chat-item-list-renderer[class] {
        overflow-anchor: initial !important; /* whenever ENABLE_OVERFLOW_ANCHOR or not */
    }

    html item-anchor {

        height: 1px;
        width: 1px;
        top: auto;
        left: auto;
        right: auto;
        bottom: auto;
        transform: translateY(-1px);
        position: absolute;
        z-index: -1;

    }

  }

  @supports (color: var(--pre-rendering)) {

    @keyframes dontRenderAnimation {
        0% {
            background-position-x: 3px;
        }
        100% {
            background-position-x: 4px;
        }
    }

    /*html[dont-render-enabled] */ .dont-render{

        visibility: collapse !important;
        transform: scale(0.01) !important;
        transform: scale(0.00001) !important;
        transform: scale(0.0000001) !important;
        transform-origin: 0 0 !important;
        z-index:-1 !important;
        contain: strict !important;
        box-sizing: border-box !important;

        height: 1px !important;
        height: 0.1px !important;
        height: 0.01px !important;
        height: 0.0001px !important;
        height: 0.000001px !important;

        animation: dontRenderAnimation 1ms linear 80ms 1 normal forwards !important;

    }

  }

  `;


  const win = typeof unsafeWindow !== 'undefined' ? unsafeWindow : (this instanceof Window ? this : window);

  // Create a unique key for the script and check if it is already running
  const hkey_script = 'mchbwnoasqph';
  if (win[hkey_script]) throw new Error('Duplicated Userscript Calling'); // avoid duplicated scripting
  win[hkey_script] = true;


  function dr(s) {
    // reserved for future use
    return s;
    // return window.deWeakJS ? window.deWeakJS(s) : s;
  }

  const getProto = (element) => {
    if (element) {
      const cnt = element.inst || element;
      return cnt.constructor.prototype || null;
    }
    return null;
  }

  const assertor = (f) => f() || console.assert(false, f + "");

  const fnIntegrity = (f, d) => {
    if (!f || typeof f !== 'function') {
      console.warn('f is not a function', f);
      return;
    }
    let p = f + "", s = 0, j = -1, w = 0;
    for (let i = 0, l = p.length; i < l; i++) {
      const t = p[i];
      if (((t >= 'a' && t <= 'z') || (t >= 'A' && t <= 'Z'))) {
        if (j < i - 1) w++;
        j = i;
      } else {
        s++;
      }
    }
    let itz = `${f.length}.${s}.${w}`;
    if (!d) {
      console.log(itz);
      return null;
    } else {
      return itz === d;
    }
  }


  console.assert(MAX_ITEMS_FOR_TOTAL_DISPLAY > 0 && MAX_ITEMS_FOR_FULL_FLUSH > 0 && MAX_ITEMS_FOR_TOTAL_DISPLAY > MAX_ITEMS_FOR_FULL_FLUSH)

  let ENABLE_FULL_RENDER_REQUIRED_CAPABLE = false;
  const isContainSupport = CSS.supports('contain', 'layout paint style');
  if (!isContainSupport) {
    console.warn("Your browser does not support css property 'contain'.\nPlease upgrade to the latest version.".trim());
  } else {
    ENABLE_FULL_RENDER_REQUIRED_CAPABLE = true;
  }

  let ENABLE_OVERFLOW_ANCHOR_CAPABLE = false;
  const isOverflowAnchorSupport = CSS.supports('overflow-anchor', 'auto');
  if (!isOverflowAnchorSupport) {
    console.warn("Your browser does not support css property 'overflow-anchor'.\nPlease upgrade to the latest version.".trim());
  } else {
    ENABLE_OVERFLOW_ANCHOR_CAPABLE = true;
  }

  const NOT_FIREFOX = !CSS.supports('-moz-appearance', 'none'); // 1. Firefox does not have the flicking issue; 2. Firefox's OVERFLOW_ANCHOR is less effective than Chromium's.

  const ENABLE_OVERFLOW_ANCHOR = ENABLE_OVERFLOW_ANCHOR_PREFERRED && ENABLE_OVERFLOW_ANCHOR_CAPABLE && ENABLE_NO_SMOOTH_TRANSFORM;
  const ENABLE_FULL_RENDER_REQUIRED = ENABLE_FULL_RENDER_REQUIRED_PREFERRED && ENABLE_FULL_RENDER_REQUIRED_CAPABLE && ENABLE_OVERFLOW_ANCHOR && ENABLE_NO_SMOOTH_TRANSFORM && NOT_FIREFOX;


  const fxOperator = (proto, propertyName) => {
    let propertyDescriptorGetter = null;
    try {
      propertyDescriptorGetter = Object.getOwnPropertyDescriptor(proto, propertyName).get;
    } catch (e) { }
    return typeof propertyDescriptorGetter === 'function' ? (e) => {
      try {

        return propertyDescriptorGetter.call(dr(e));
      } catch (e) { }
      return e[propertyName];
    } : (e) => e[propertyName];
  };

  const nodeParent = fxOperator(Node.prototype, 'parentNode');
  // const nFirstElem = fxOperator(HTMLElement.prototype, 'firstElementChild');
  const nPrevElem = fxOperator(HTMLElement.prototype, 'previousElementSibling');
  const nNextElem = fxOperator(HTMLElement.prototype, 'nextElementSibling');
  const nLastElem = fxOperator(HTMLElement.prototype, 'lastElementChild');


  const groupCollapsed = (text1, text2) => {

    console.groupCollapsed(`%c${text1}%c${text2}`,
      "background-color: #010502; color: #6acafe; font-weight: 700; padding: 2px;",
      "background-color: #010502; color: #6ad9fe; font-weight: 300; padding: 2px;"
    );
  }


  /* globals WeakRef:false */

  /** @type {(o: Object | null) => WeakRef | null} */
  const mWeakRef = typeof WeakRef === 'function' ? (o => o ? new WeakRef(o) : null) : (o => o || null); // typeof InvalidVar == 'undefined'

  /** @type {(wr: Object | null) => Object | null} */
  const kRef = (wr => (wr && wr.deref) ? wr.deref() : wr);

  const { addCssManaged } = (() => {

    const addFontPreRendering = () => {

      groupCollapsed("YouTube Super Fast Chat", " | Fonts Pre-Rendering");

      let efsContainer = document.createElement('elzm-fonts');
      efsContainer.id = 'elzm-fonts-yk75g'

      const arr = [];
      let p = document.createElement('elzm-font');
      arr.push(p);

      if (ENABLE_FONT_PRE_RENDERING & 1) {
        for (const size of [100, 200, 300, 400, 500, 600, 700, 800, 900]) {

          p = document.createElement('elzm-font');
          p.style.fontWeight = size;
          arr.push(p);
        }
      }

      if (ENABLE_FONT_PRE_RENDERING & 2) {
        for (const size of [100, 200, 300, 400, 500, 600, 700, 800, 900]) {

          p = document.createElement('elzm-font');
          p.style.fontFamily = 'Roboto';
          p.style.fontWeight = size;
          arr.push(p);
        }
      }

      if (ENABLE_FONT_PRE_RENDERING & 4) {
        for (const size of [100, 200, 300, 400, 500, 600, 700, 800, 900]) {

          p = document.createElement('elzm-font');
          p.style.fontFamily = '"YouTube Noto",Roboto,Arial,Helvetica,sans-serif';
          p.style.fontWeight = size;
          arr.push(p);
        }
      }


      if (ENABLE_FONT_PRE_RENDERING & 8) {
        for (const size of [100, 200, 300, 400, 500, 600, 700, 800, 900]) {

          p = document.createElement('elzm-font');
          p.style.fontFamily = '"Noto",Roboto,Arial,Helvetica,sans-serif';
          p.style.fontWeight = size;
          arr.push(p);
        }
      }


      if (ENABLE_FONT_PRE_RENDERING & 16) {
        for (const size of [100, 200, 300, 400, 500, 600, 700, 800, 900]) {

          p = document.createElement('elzm-font');
          p.style.fontFamily = 'sans-serif';
          p.style.fontWeight = size;
          arr.push(p);
        }
      }

      console.log('number of elzm-font elements', arr.length);

      HTMLElement.prototype.append.apply(efsContainer, arr);

      (document.body || document.documentElement).appendChild(efsContainer);


      console.log('elzm-font elements have been added to the page for rendering.');

      console.groupEnd();

    }

    let isCssAdded = false;

    function addCssElement() {
      let s = document.createElement('style');
      s.id = 'ewRvC';
      return s;
    }

    const addCssManaged = () => {
      if (!isCssAdded && document.documentElement && document.head) {
        isCssAdded = true;
        document.head.appendChild(dr(addCssElement())).textContent = addCss();
        if (ENABLE_FONT_PRE_RENDERING) {
          Promise.resolve().then(addFontPreRendering)
        }
      }
    }

    return { addCssManaged };
  })();


  const { setupStyle } = (() => {

    const sp7 = Symbol();

    const proxyHelperFn = (dummy) => ({

      get(target, prop) {
        return (prop in dummy) ? dummy[prop] : prop === sp7 ? target : target[prop];
      },
      set(target, prop, value) {
        if (!(prop in dummy)) {
          target[prop] = value;
        }
        return true;
      },
      has(target, prop) {
        return (prop in target);
      },
      deleteProperty(target, prop) {
        return true;
      },
      ownKeys(target) {
        return Object.keys(target);
      },
      defineProperty(target, key, descriptor) {
        return Object.defineProperty(target, key, descriptor);
      },
      getOwnPropertyDescriptor(target, key) {
        return Object.getOwnPropertyDescriptor(target, key);
      },

    });

    const setupStyle = (m1, m2) => {
      if (!ENABLE_NO_SMOOTH_TRANSFORM) return;

      const dummy1v = {
        transform: '',
        height: '',
        minHeight: '',
        paddingBottom: '',
        paddingTop: ''
      };

      const dummyStyleFn = (k) => (function () { const style = this[sp7]; return style[k](...arguments); });
      for (const k of ['toString', 'getPropertyPriority', 'getPropertyValue', 'item', 'removeProperty', 'setProperty']) {
        dummy1v[k] = dummyStyleFn(k);
      }

      const dummy1p = proxyHelperFn(dummy1v);
      const sp1v = new Proxy(m1.style, dummy1p);
      const sp2v = new Proxy(m2.style, dummy1p);
      Object.defineProperty(m1, 'style', { get() { return sp1v }, set() { }, enumerable: true, configurable: true });
      Object.defineProperty(m2, 'style', { get() { return sp2v }, set() { }, enumerable: true, configurable: true });
      m1.removeAttribute("style");
      m2.removeAttribute("style");

    }

    return { setupStyle };

  })();


  const cleanContext = async (win) => {
    const waitFn = requestAnimationFrame; // shall have been binded to window
    try {
      let mx = 16; // MAX TRIAL
      const frameId = 'vanillajs-iframe-v1';
      /** @type {HTMLIFrameElement | null} */
      let frame = document.getElementById(frameId);
      let removeIframeFn = null;
      if (!frame) {
        frame = document.createElement('iframe');
        frame.id = 'vanillajs-iframe-v1';
        frame.sandbox = 'allow-same-origin'; // script cannot be run inside iframe but API can be obtained from iframe
        let n = document.createElement('noscript'); // wrap into NOSCRPIT to avoid reflow (layouting)
        n.appendChild(frame);
        while (!document.documentElement && mx-- > 0) await new Promise(waitFn); // requestAnimationFrame here could get modified by YouTube engine
        const root = document.documentElement;
        root.appendChild(n); // throw error if root is null due to exceeding MAX TRIAL
        removeIframeFn = (setTimeout) => {
          const removeIframeOnDocumentReady = (e) => {
            e && win.removeEventListener("DOMContentLoaded", removeIframeOnDocumentReady, false);
            win = null;
            setTimeout(() => {
              n.remove();
              n = null;
            }, 200);
          }
          if (document.readyState !== 'loading') {
            removeIframeOnDocumentReady();
          } else {
            win.addEventListener("DOMContentLoaded", removeIframeOnDocumentReady, false);
          }
        }
      }
      while (!frame.contentWindow && mx-- > 0) await new Promise(waitFn);
      const fc = frame.contentWindow;
      if (!fc) throw "window is not found."; // throw error if root is null due to exceeding MAX TRIAL
      const { requestAnimationFrame, setTimeout, cancelAnimationFrame } = fc;
      const res = { requestAnimationFrame, setTimeout, cancelAnimationFrame };
      for (let k in res) res[k] = res[k].bind(win); // necessary
      if (removeIframeFn) Promise.resolve(res.setTimeout).then(removeIframeFn);
      return res;
    } catch (e) {
      console.warn(e);
      return null;
    }
  };

  cleanContext(win).then(__CONTEXT__ => {
    if (!__CONTEXT__) return null;


    const { requestAnimationFrame, setTimeout, cancelAnimationFrame } = __CONTEXT__;


    (() => {
      // data manipulation

      if (!DO_PARTICIPANT_LIST_HACKS) return;

      class Mutex {

        constructor() {
          this.p = Promise.resolve()
        }

        /**
         *  @param {(lockResolve: () => void)} f
         */
        lockWith(f) {
          this.p = this.p.then(() => new Promise(f).catch(console.warn))
        }

      }


      /**
   
       h.onParticipantsChanged = function() {
          this.notifyPath("participantsManager.participants")
      }
   
   
      at h.onParticipantsChanged (live_chat_polymer.js:8334:41)
      at e.<anonymous> (live_chat_polymer.js:1637:69)
      at e.Bb [as __shady_dispatchEvent] (webcomponents-sd.js:46:110)
      at k.dispatchEvent (webcomponents-sd.js:122:237)
      at mu (live_chat_polymer.js:1677:71)
      at Object.wga [as fn] (live_chat_polymer.js:1678:99)
      at a._propertiesChanged (live_chat_polymer.js:1726:426)
      at b._flushProperties (live_chat_polymer.js:1597:200)
      at a._invalidateProperties (live_chat_polymer.js:1718:69)
      at a.notifyPath (live_chat_polymer.js:1741:182)
   
      */


      const beforeParticipantsMap = new WeakMap();

      const { notifyPath7081 } = (() => {


        const foundMap = (base, content) => {

          let lastSearch = 0;
          let founds = base.map(baseEntry => {
            let search = content.indexOf(baseEntry, lastSearch);
            if (search < 0) return false;
            lastSearch = search + 1;
            return true;
          });
          return founds;


        }



        const spliceIndicesFunc = (beforeParticipants, participants, idsBefore, idsAfter) => {

          const handler1 = {
            get(target, prop, receiver) {
              if (prop === 'object') {
                return participants; // avoid memory leakage
              }
              if (prop === 'type') {
                return 'splice';
              }
              return target[prop];
            }
          };
          const releaser = () => {
            beforeParticipants = null;
            participants = null;
            idsBefore = null;
            idsAfter = null;
          }


          let foundsForAfter = foundMap(idsAfter, idsBefore);
          let foundsForBefore = foundMap(idsBefore, idsAfter);

          let indexSplices = [];
          let contentUpdates = [];
          for (let i = 0, j = 0; i < foundsForBefore.length || j < foundsForAfter.length;) {

            if (beforeParticipants[i] === participants[j]) {
              i++; j++;
            } else if (idsBefore[i] === idsAfter[j]) {
              // content changed
              contentUpdates.push({ indexI: i, indexJ: j })
              i++; j++;
            } else {
              let addedCount = 0;
              for (let q = j; q < foundsForAfter.length; q++) {
                if (foundsForAfter[q] === false) addedCount++;
                else break;
              }

              let removedCount = 0;
              for (let q = i; q < foundsForBefore.length; q++) {
                if (foundsForBefore[q] === false) removedCount++;
                else break;
              }
              if (!addedCount && !removedCount) {
                throw 'ERROR(0xFF32): spliceIndicesFunc';
              }
              indexSplices.push(new Proxy({
                index: j,
                addedCount: addedCount,
                removed: removedCount >= 1 ? beforeParticipants.slice(i, i + removedCount) : []
              }, handler1));

              i += removedCount;
              j += addedCount;

            }
          }
          return { indexSplices, contentUpdates, releaser };


        }

        const mutexParticipants = new Mutex();


        /*
     
        customElements.get("yt-live-chat-participant-renderer").prototype.notifyPath=function(){  console.log(123);  console.log(new Error().stack)}
     
        VM63631:1 Error
        at customElements.get.notifyPath (<anonymous>:1:122)
        at e.forwardRendererStamperChanges_ (live_chat_polymer.js:4453:35)
        at e.rendererStamperApplyChangeRecord_ (live_chat_polymer.js:4451:12)
        at e.rendererStamperObserver_ (live_chat_polymer.js:4448:149)
        at Object.pu [as fn] (live_chat_polymer.js:1692:118)
        at ju (live_chat_polymer.js:1674:217)
        at a._propertiesChanged (live_chat_polymer.js:1726:122)
        at b._flushProperties (live_chat_polymer.js:1597:200)
        at a._invalidateProperties (live_chat_polymer.js:1718:69)
        at a.notifyPath (live_chat_polymer.js:1741:182)
     
        */

        function convertToIds(participants) {
          return participants.map(participant => {
            if (!participant || typeof participant !== 'object') {
              console.warn('Error(0xFA41): convertToIds', participant);
              return participant; // just in case
            }
            let keys = Object.keys(participant);
            // liveChatTextMessageRenderer
            // liveChatParticipantRenderer - livestream channel owner [no authorExternalChannelId]
            // liveChatPaidMessageRenderer
            /*
     
            'yt-live-chat-participant-renderer' utilizes the following:
            authorName.simpleText: string
            authorPhoto.thumbnails: Object{url:string, width:int, height:int} []
            authorBadges[].liveChatAuthorBadgeRenderer.icon.iconType: string
            authorBadges[].liveChatAuthorBadgeRenderer.tooltip: string
            authorBadges[].liveChatAuthorBadgeRenderer.accessibility.accessibilityData: Object{label:string}
     
            */
            if (keys.length !== 1) {
              console.warn('Error(0xFA42): convertToIds', participant);
              return participant; // just in case
            }
            let key = keys[0];
            let renderer = (participant[key] || 0);
            let authorName = (renderer.authorName || 0);
            let text = `${authorName.simpleText || authorName.text}`
            let res = participant; // fallback if it is not a vaild entry
            if (typeof text !== 'string') {
              console.warn('Error(0xFA53): convertToIds', participant);
            } else {
              text = `${renderer.authorExternalChannelId || 'null'}|${text || ''}`;
              if (text.length > 1) res = text;
            }
            return res;
            // return renderer?`${renderer.id}|${renderer.authorExternalChannelId}`: '';
            // note: renderer.id will be changed if the user typed something to trigger the update of the participants' record.
          });
        }

        const checkChangeToParticipantRendererContent = CHECK_CHANGE_TO_PARTICIPANT_RENDERER_CONTENT ? (p1, p2) => {
          // just update when content is changed.
          if (p1.authorName !== p2.authorName) return true;
          if (p1.authorPhoto !== p2.authorPhoto) return true;
          if (p1.authorBadges !== p2.authorBadges) return true;
          return false;
        } : (p1, p2) => {
          // keep integrity all the time.
          return p1 !== p2; // always true
        }

        let uvid = 0;

        function notifyPath7081(path) { // cnt "yt-live-chat-participant-list-renderer"

          let stack = new Error().stack;
          if (path !== "participantsManager.participants" || stack.indexOf('.onParticipantsChanged') < 0) {
            return this.__notifyPath5036__.apply(this, arguments);
          }

          if (uvid > 1e8) uvid = uvid % 100;
          let tid = ++uvid;

          const cnt = this; // "yt-live-chat-participant-list-renderer"
          mutexParticipants.lockWith(lockResolve => {

            if (tid !== uvid) {
              lockResolve();
              return;
            }

            const participants = cnt.participantsManager.participants.slice(0);
            const beforeParticipants = beforeParticipantsMap.get(cnt) || [];
            beforeParticipantsMap.set(cnt, participants);

            const resPromise = (async () => {

              if (beforeParticipants.length === 0) {
                // not error
                return 0;
              }

              let countOfElements = cnt.__getAllParticipantsDOMRenderedLength__()

              // console.log(participants.length, doms.length) // different if no requestAnimationFrame
              if (beforeParticipants.length !== countOfElements) {
                // there is somewrong for the cache. - sometimes happen
                return 0;
              }

              const idsBefore = convertToIds(beforeParticipants);
              const idsAfter = convertToIds(participants);

              let { indexSplices, contentUpdates, releaser } = spliceIndicesFunc(beforeParticipants, participants, idsBefore, idsAfter);

              let res = 1; // default 1 for no update

              if (indexSplices.length >= 1) {


                // let p2 =  participants.slice(indexSplices[0].index, indexSplices[0].index+indexSplices[0].addedCount);
                // let p1 = indexSplices[0].removed;
                // console.log(indexSplices.length, indexSplices ,p1,p2,  convertToIds(p1),convertToIds(p2))

                /* folllow
                    a.notifyPath(c + ".splices", d);
                    a.notifyPath(c + ".length", b.length);
                */
                // stampDomArraySplices_


                await new Promise(resolve => {
                  cnt.resolveForDOMRendering781 = resolve;

                  cnt.__notifyPath5036__("participantsManager.participants.splices", {
                    indexSplices
                  });
                  indexSplices = null;
                  releaser();
                  releaser = null;
                  cnt.__notifyPath5036__("participantsManager.participants.length",
                    participants.length
                  );

                });

                await Promise.resolve(0); // play safe for the change of 'length'
                countOfElements = cnt.__getAllParticipantsDOMRenderedLength__();

                let wrongSize = participants.length !== countOfElements
                if (wrongSize) {
                  console.warn("ERROR(0xE2C3): notifyPath7081", beforeParticipants.length, participants.length, doms.length)
                  return 0;
                }

                res = 2 | 4;

              } else {

                indexSplices = null;
                releaser();
                releaser = null;

                if (participants.length !== countOfElements) {
                  // other unhandled cases
                  return 0;
                }

              }

              // participants.length === countOfElements before contentUpdates
              if (contentUpdates.length >= 1) {
                for (const contentUpdate of contentUpdates) {
                  let isChanged = checkChangeToParticipantRendererContent(beforeParticipants[contentUpdate.indexI], participants[contentUpdate.indexJ]);
                  if (isChanged) {
                    cnt.__notifyPath5036__(`participantsManager.participants[${contentUpdate.indexJ}]`);
                    res |= 4 | 8;
                  }
                }
              }
              contentUpdates = null;

              return res;


            })();


            resPromise.then(resValue => {

              const isLogRequired = SHOW_PARTICIPANT_CHANGES_IN_CONSOLE && ((resValue === 0) || ((resValue & 4) === 4));
              isLogRequired && groupCollapsed("Participant List Change", `tid = ${tid}; res = ${resValue}`);
              if (resValue === 0) {
                new Promise(resolve => {
                  cnt.resolveForDOMRendering781 = resolve;
                  isLogRequired && console.log("Full Refresh begins");
                  cnt.__notifyPath5036__("participantsManager.participants"); // full refresh
                }).then(() => {
                  isLogRequired && console.log("Full Refresh ends");
                  console.groupEnd();
                }).then(lockResolve);
                return;
              }

              const delayLockResolve = (resValue & 4) === 4;

              if (delayLockResolve) {
                isLogRequired && console.log(`Number of participants (before): ${beforeParticipants.length}`);
                isLogRequired && console.log(`Number of participants (after): ${participants.length}`);
                isLogRequired && console.log(`Total number of rendered participants: ${cnt.__getAllParticipantsDOMRenderedLength__()}`);
                isLogRequired && console.log(`Participant Renderer Content Updated: ${(resValue & 8) === 8}`);
                isLogRequired && console.groupEnd();
                // requestAnimationFrame is required to avoid particiant update during DOM changing (stampDomArraySplices_)
                // mutex lock with requestAnimationFrame can also disable participants update in background
                requestAnimationFrame(lockResolve);
              } else {
                lockResolve();
              }

            });

          });


        }

        return { notifyPath7081 };

      })();


      const onRegistryReadyForDataManipulation = () => {

        function dummy5035(a, b, c) { }
        function dummy411(a, b, c) { }

        customElements.whenDefined("yt-live-chat-participant-list-renderer").then(() => {

          if (!DO_PARTICIPANT_LIST_HACKS) return;

          const tag = "yt-live-chat-participant-list-renderer"
          const cProto = getProto(document.createElement(tag));
          if (!cProto || typeof cProto.attached !== 'function') {
            // for _registered, proto.attached shall exist when the element is defined.
            // for controller extraction, attached shall exist when instance creates.
            console.warn(`proto.attached for ${tag} is unavailable.`);
            return;
          }


          groupCollapsed("YouTube Super Fast Chat", " | yt-live-chat-participant-list-renderer hacks");

          const canDoReplacement = (() => {
            if (typeof cProto.__notifyPath5035__ === 'function' && cProto.__notifyPath5035__.name !== 'dummy5035') {
              console.warn('YouTube Live Chat Tamer is running.');
              return;
            }

            if (typeof cProto.__attached411__ === 'function' && cProto.__attached411__.name !== 'dummy411') {
              console.warn('YouTube Live Chat Tamer is running.');
              return;
            }

            cProto.__notifyPath5035__ = dummy5035 // just to against Live Chat Tamer
            cProto.__attached411__ = dummy411 // just to against Live Chat Tamer

            if (typeof cProto.flushRenderStamperComponentBindings_ !== 'function' || cProto.flushRenderStamperComponentBindings_.length !== 0) {
              console.warn("ERROR(0xE355): cProto.flushRenderStamperComponentBindings_ not found");
              return;
            }

            if (typeof cProto.flushRenderStamperComponentBindings66_ === 'function') {
              console.warn("ERROR(0xE356): cProto.flushRenderStamperComponentBindings66_");
              return;
            }

            if (typeof cProto.__getAllParticipantsDOMRenderedLength__ === 'function') {
              console.warn("ERROR(0xE357): cProto.__getAllParticipantsDOMRenderedLength__");
              return;
            }
            return true;
          })();

          console.log(`Data Manipulation Boost = ${canDoReplacement}`);


          assertor(() => fnIntegrity(cProto.attached, '0.32.22')) // just warning
          assertor(() => fnIntegrity(cProto.flushRenderStamperComponentBindings_, '0.385.233')) // just warning


          cProto.flushRenderStamperComponentBindings66_ = cProto.flushRenderStamperComponentBindings_;

          cProto.flushRenderStamperComponentBindings_ = function () {
            // console.log('flushRenderStamperComponentBindings_')
            this.flushRenderStamperComponentBindings66_();
            if (this.resolveForDOMRendering781) {
              this.resolveForDOMRendering781();
              this.resolveForDOMRendering781 = null;
            }
          }

          cProto.__getAllParticipantsDOMRenderedLength__ = function () {
            const container = this.$.participants;
            return HTMLElement.prototype.querySelectorAll.call(container, 'yt-live-chat-participant-renderer').length;
          }

          const onPageElements = [...document.querySelectorAll('yt-live-chat-participant-list-renderer:not(.n9fJ3)')];

          cProto.__attached412__ = cProto.attached;
          const fpPList = function (hostElement) {
            const cnt = hostElement.inst || hostElement;
            if (beforeParticipantsMap.has(cnt)) return;
            hostElement.classList.add('n9fJ3');

            if (cnt.isAttached !== true && (!cnt.__dataEnabled || !cnt.__dataReady)) {
              // somehow it is a bug in Waterfox Classic.
              return;
            }

            assertor(() => (cnt.__dataEnabled === true && cnt.__dataReady === true));
            if (typeof cnt.notifyPath !== 'function' || typeof cnt.__notifyPath5036__ !== 'undefined') {
              console.warn("ERROR(0xE318): yt-live-chat-participant-list-renderer")
              return;
            }

            groupCollapsed("Participant List attached", "");
            // cnt.$.participants.appendChild = cnt.$.participants.__shady_native_appendChild =  function(){
            //   console.log(123, 'appendChild');
            //   return HTMLElement.prototype.appendChild.apply(this, arguments)
            // }

            // cnt.$.participants.insertBefore =cnt.$.participants.__shady_native_insertBefore =  function(){
            //   console.log(123, 'insertBefore');
            //   return HTMLElement.prototype.insertBefore.apply(this, arguments)
            // }

            cnt.__notifyPath5036__ = cnt.notifyPath
            const participants = ((cnt.participantsManager || 0).participants || 0);
            assertor(() => (participants.length > -1 && typeof participants.slice === 'function'));
            console.log(`initial number of participants: ${participants.length}`);
            const newParticipants = (participants.length >= 1 && typeof participants.slice === 'function') ? participants.slice(0) : [];
            beforeParticipantsMap.set(cnt, newParticipants);
            cnt.notifyPath = notifyPath7081;
            console.log(`CHECK_CHANGE_TO_PARTICIPANT_RENDERER_CONTENT = ${CHECK_CHANGE_TO_PARTICIPANT_RENDERER_CONTENT}`);
            console.groupEnd();
          }
          cProto.attached = function () {
            fpPList(this.hostElement || this);
            this.__attached412__.apply(this, arguments);
          };

          console.groupEnd();

          if (onPageElements.length >= 1) {
            for (const s of onPageElements) {
              fpPList(s);
            }
          }

        });

      };

      customYtElements.onRegistryReady(onRegistryReadyForDataManipulation);


    })();

    IntersectionObserver && (() => {

      // dom manipulation

      class RAFHub {
        constructor() {
          /** @type {number} */
          this.startAt = 8170;
          /** @type {number} */
          this.counter = 0;
          /** @type {number} */
          this.rid = 0;
          /** @type {Map<number, FrameRequestCallback>} */
          this.funcs = new Map();
          const funcs = this.funcs;
          /** @type {FrameRequestCallback} */
          this.bCallback = this.mCallback.bind(this);
          this.pClear = () => funcs.clear();
        }
        /** @param {DOMHighResTimeStamp} highResTime */
        mCallback(highResTime) {
          this.rid = 0;
          Promise.resolve().then(this.pClear);
          this.funcs.forEach(func => Promise.resolve(highResTime).then(func).catch(console.warn));
        }
        /** @param {FrameRequestCallback} f */
        request(f) {
          if (this.counter > 1e9) this.counter = 9;
          let cid = this.startAt + (++this.counter);
          this.funcs.set(cid, f);
          if (this.rid === 0) this.rid = requestAnimationFrame(this.bCallback);
          return cid;
        }
        /** @param {number} cid */
        cancel(cid) {
          cid = +cid;
          if (cid > 0) {
            if (cid <= this.startAt) {
              return cancelAnimationFrame(cid);
            }
            if (this.rid > 0) {
              this.funcs.delete(cid);
              if (this.funcs.size === 0) {
                cancelAnimationFrame(this.rid);
                this.rid = 0;
              }
            }
          }
        }
      }


      const rafHub = (ENABLE_RAF_HACK_TICKERS || ENABLE_RAF_HACK_DOCKED_MESSAGE || ENABLE_RAF_HACK_INPUT_RENDERER || ENABLE_RAF_HACK_EMOJI_PICKER) ? new RAFHub() : null;


      let dt0 = Date.now() - 2000;
      const dateNow = () => Date.now() - dt0;
      // let lastScroll = 0;
      // let lastLShow = 0;
      let lastWheel = 0;
      let lastMouseDown = 0;
      let lastMouseUp = 0;
      let currentMouseDown = false;
      let lastTouchDown = 0;
      let lastTouchUp = 0;
      let currentTouchDown = false;
      let lastUserInteraction = 0;

      let scrollChatFn = null;

      ENABLE_FULL_RENDER_REQUIRED && (() => {

        document.addEventListener('animationstart', (evt) => {

          if (evt.animationName === 'dontRenderAnimation') {
            evt.target.classList.remove('dont-render');
            if (scrollChatFn) scrollChatFn();
          }

        }, true);

        const f = (elm) => {
          if (elm && elm.nodeType === 1) {
            elm.classList.add('dont-render');
          }
        }

        Node.prototype.__appendChild931__ = function (a) {
          a = dr(a);
          if (this.id === 'items' && this.classList.contains('yt-live-chat-item-list-renderer')) {
            if (a && a.nodeType === 1) f(a);
            else if (a instanceof DocumentFragment) {
              for (let n = a.firstChild; n; n = n.nextSibling) {
                f(n);
              }
            }
          }
        }

        Node.prototype.__appendChild932__ = function () {
          this.__appendChild931__.apply(this, arguments);
          return Node.prototype.appendChild.apply(this, arguments);
        }


      })();


      const watchUserCSS = () => {

        // if (!CSS.supports('contain-intrinsic-size', 'auto var(--wsr94)')) return;

        const getElemFromWR = (nr) => {
          const n = kRef(nr);
          if (n && n.isConnected) return n;
          return null;
        }

        const clearContentVisibilitySizing = () => {
          Promise.resolve().then(() => {

            let btnShowMoreWR = mWeakRef(document.querySelector('#show-more[disabled]'));

            let lastVisibleItemWR = null;
            for (const elm of document.querySelectorAll('[wSr93]')) {
              if (elm.getAttribute('wSr93') === 'visible') lastVisibleItemWR = mWeakRef(elm);
              elm.setAttribute('wSr93', '');
              // custom CSS property --wsr94 not working when attribute wSr93 removed
            }
            requestAnimationFrame(() => {
              const btnShowMore = getElemFromWR(btnShowMoreWR); btnShowMoreWR = null;
              if (btnShowMore) btnShowMore.click();
              else {
                // would not work if switch it frequently
                const lastVisibleItem = getElemFromWR(lastVisibleItemWR); lastVisibleItemWR = null;
                if (lastVisibleItem) {

                  Promise.resolve()
                    .then(() => lastVisibleItem.scrollIntoView())
                    .then(() => lastVisibleItem.scrollIntoView(false))
                    .then(() => lastVisibleItem.scrollIntoView({ behavior: "instant", block: "end", inline: "nearest" }))
                    .catch(e => { }) // break the chain when method not callable

                }
              }
            });

          });

        }

        const mutObserver = new MutationObserver((mutations) => {
          for (const mutation of mutations) {
            if ((mutation.addedNodes || 0).length >= 1) {
              for (const addedNode of mutation.addedNodes) {
                if (addedNode.nodeName === 'STYLE') {
                  clearContentVisibilitySizing();
                  return;
                }
              }
            }
            if ((mutation.removedNodes || 0).length >= 1) {
              for (const removedNode of mutation.removedNodes) {
                if (removedNode.nodeName === 'STYLE') {
                  clearContentVisibilitySizing();
                  return;
                }
              }
            }
          }
        });

        mutObserver.observe(document.documentElement, {
          childList: true,
          subtree: false
        });
        mutObserver.observe(document.head, {
          childList: true,
          subtree: false
        });
        mutObserver.observe(document.body, {
          childList: true,
          subtree: false
        });

      }


      class WillChangeController {
        constructor(itemScroller, willChangeValue) {
          this.element = itemScroller;
          this.counter = 0;
          this.active = false;
          this.willChangeValue = willChangeValue;
        }

        beforeOper() {
          if (!this.active) {
            this.active = true;
            this.element.style.willChange = this.willChangeValue;
          }
          this.counter++;
        }

        afterOper() {
          const c = this.counter;
          requestAnimationFrame(() => {
            if (c === this.counter) {
              this.active = false;
              this.element.style.willChange = '';
            }
          });
        }

        release() {
          const element = this.element;
          this.element = null;
          this.counter = 1e16;
          this.active = false;
          try {
            element.style.willChange = '';
          } catch (e) { }
        }

      }


      const { lcRendererElm, visObserver } = (() => {



        let lcRendererWR = null;

        const lcRendererElm = () => {
          let lcRenderer = kRef(lcRendererWR);
          if (!lcRenderer || !lcRenderer.isConnected) {
            lcRenderer = document.querySelector('yt-live-chat-item-list-renderer.yt-live-chat-renderer');
            lcRendererWR = lcRenderer ? mWeakRef(lcRenderer) : null;
          }
          return lcRenderer;
        };


        let hasFirstShowMore = false;

        const visObserverFn = (entry) => {

          const target = entry.target;
          if (!target) return;
          // if(target.classList.contains('dont-render')) return;
          let isVisible = entry.isIntersecting === true && entry.intersectionRatio > 0.5;
          // const h = entry.boundingClientRect.height;
          /*
          if (h < 16) { // wrong: 8 (padding/margin); standard: 32; test: 16 or 20
              // e.g. under fullscreen. the element created but not rendered.
              target.setAttribute('wSr93', '');
              return;
          }
          */
          if (isVisible) {
            // target.style.setProperty('--wsr94', h + 'px');
            target.setAttribute('wSr93', 'visible');
            if (nNextElem(target) === null) {

              // firstVisibleItemDetected = true;
              /*
                if (dateNow() - lastScroll < 80) {
                    lastLShow = 0;
                    lastScroll = 0;
                    Promise.resolve().then(clickShowMore);
                } else {
                    lastLShow = dateNow();
                }
                */
              // lastLShow = dateNow();
            } else if (!hasFirstShowMore) { // should more than one item being visible
              // implement inside visObserver to ensure there is sufficient delay
              hasFirstShowMore = true;
              requestAnimationFrame(() => {
                // foreground page
                // page visibly ready -> load the latest comments at initial loading
                const lcRenderer = lcRendererElm();
                if (lcRenderer) {
                  (lcRenderer.inst || lcRenderer).scrollToBottom_();
                }
              });
            }
          }
          else if (target.getAttribute('wSr93') === 'visible') { // ignore target.getAttribute('wSr93') === '' to avoid wrong sizing

            // target.style.setProperty('--wsr94', h + 'px');
            target.setAttribute('wSr93', 'hidden');
          } // note: might consider 0 < entry.intersectionRatio < 0.5 and target.getAttribute('wSr93') === '' <new last item>

        }



        const visObserver = new IntersectionObserver((entries) => {

          for (const entry of entries) {

            Promise.resolve(entry).then(visObserverFn);

          }

        }, {
          // root: HTMLElement.prototype.closest.call(m2, '#item-scroller.yt-live-chat-item-list-renderer'), // nullable
          rootMargin: "0px",
          threshold: [0.05, 0.95],
        });


        return { lcRendererElm, visObserver }


      })();

      const { setupMutObserver } = (() => {

        const mutFn = (items) => {
          for (let node = nLastElem(items); node !== null; node = nPrevElem(node)) {
            if (node.hasAttribute('wSr93')) break;
            node.setAttribute('wSr93', '');
            visObserver.observe(node);
          }
        }

        const mutObserver = new MutationObserver((mutations) => {
          const items = (mutations[0] || 0).target;
          if (!items) return;
          mutFn(items);
        });

        const setupMutObserver = (m2) => {
          scrollChatFn = null;
          mutObserver.disconnect();
          mutObserver.takeRecords();
          if (m2) {
            if (typeof m2.__appendChild932__ === 'function') {
              if (typeof m2.appendChild === 'function') m2.appendChild = m2.__appendChild932__;
              if (typeof m2.__shady_native_appendChild === 'function') m2.__shady_native_appendChild = m2.__appendChild932__;
            }
            mutObserver.observe(m2, {
              childList: true,
              subtree: false
            });
            mutFn(m2);


            if (ENABLE_OVERFLOW_ANCHOR) {

              let items = m2;
              let addedAnchor = false;
              if (items) {
                if (items.nextElementSibling === null) {
                  items.classList.add('no-anchor');
                  addedAnchor = true;
                  items.parentNode.appendChild(dr(document.createElement('item-anchor')));
                }
              }



              if (addedAnchor) {
                nodeParent(m2).classList.add('no-anchor'); // required
              }

            }

            // let div = document.createElement('div');
            // div.id = 'qwcc';
            // HTMLElement.prototype.appendChild.call(document.querySelector('yt-live-chat-item-list-renderer'), div )
            // bufferRegion =div;

            // buffObserver.takeRecords();
            // buffObserver.disconnect();
            // buffObserver.observe(div,  {
            //     childList: true,
            //     subtree: false
            // })



          }
        }

        return { setupMutObserver };



      })();

      const setupEvents = () => {


        let scrollCount = 0;

        const passiveCapture = typeof IntersectionObserver === 'function' ? { capture: true, passive: true } : true;


        const delayFlushActiveItemsAfterUserActionK_ = () => {

          const lcRenderer = lcRendererElm();
          if (lcRenderer) {
            const cnt = (lcRenderer.inst || lcRenderer);
            if (!cnt.hasUserJustInteracted11_) return;
            if (cnt.atBottom && cnt.allowScroll && cnt.activeItems_.length >= 1 && cnt.hasUserJustInteracted11_()) {
              cnt.delayFlushActiveItemsAfterUserAction11_ && cnt.delayFlushActiveItemsAfterUserAction11_();
            }
          }

        }

        document.addEventListener('scroll', (evt) => {
          if (!evt || !evt.isTrusted) return;
          // lastScroll = dateNow();
          if (++scrollCount > 1e9) scrollCount = 9;
        }, passiveCapture); // support contain => support passive

        let lastScrollCount = -1;
        document.addEventListener('wheel', (evt) => {
          if (!evt || !evt.isTrusted) return;
          if (lastScrollCount === scrollCount) return;
          lastScrollCount = scrollCount;
          lastWheel = dateNow();
          delayFlushActiveItemsAfterUserActionK_ && delayFlushActiveItemsAfterUserActionK_();
        }, passiveCapture); // support contain => support passive

        document.addEventListener('mousedown', (evt) => {
          if (!evt || !evt.isTrusted) return;
          if (((evt || 0).target || 0).id !== 'item-scroller') return;
          lastMouseDown = dateNow();
          currentMouseDown = true;
          lastUserInteraction = lastMouseDown;
        }, passiveCapture);

        document.addEventListener('pointerdown', (evt) => {
          if (!evt || !evt.isTrusted) return;
          if (((evt || 0).target || 0).id !== 'item-scroller') return;
          lastMouseDown = dateNow();
          currentMouseDown = true;
          lastUserInteraction = lastMouseDown;
        }, passiveCapture);

        document.addEventListener('click', (evt) => {
          if (!evt || !evt.isTrusted) return;
          if (((evt || 0).target || 0).id !== 'item-scroller') return;
          lastMouseDown = lastMouseUp = dateNow();
          currentMouseDown = false;
          lastUserInteraction = lastMouseDown;
          delayFlushActiveItemsAfterUserActionK_ && delayFlushActiveItemsAfterUserActionK_();
        }, passiveCapture);

        document.addEventListener('tap', (evt) => {
          if (!evt || !evt.isTrusted) return;
          if (((evt || 0).target || 0).id !== 'item-scroller') return;
          lastMouseDown = lastMouseUp = dateNow();
          currentMouseDown = false;
          lastUserInteraction = lastMouseDown;
          delayFlushActiveItemsAfterUserActionK_ && delayFlushActiveItemsAfterUserActionK_();
        }, passiveCapture);


        document.addEventListener('mouseup', (evt) => {
          if (!evt || !evt.isTrusted) return;
          if (currentMouseDown) {
            lastMouseUp = dateNow();
            currentMouseDown = false;
            lastUserInteraction = lastMouseUp;
            delayFlushActiveItemsAfterUserActionK_ && delayFlushActiveItemsAfterUserActionK_();
          }
        }, passiveCapture);


        document.addEventListener('pointerup', (evt) => {
          if (!evt || !evt.isTrusted) return;
          if (currentMouseDown) {
            lastMouseUp = dateNow();
            currentMouseDown = false;
            lastUserInteraction = lastMouseUp;
            delayFlushActiveItemsAfterUserActionK_ && delayFlushActiveItemsAfterUserActionK_();
          }
        }, passiveCapture);

        document.addEventListener('touchstart', (evt) => {
          if (!evt || !evt.isTrusted) return;
          lastTouchDown = dateNow();
          currentTouchDown = true;
          lastUserInteraction = lastTouchDown;
        }, passiveCapture);

        document.addEventListener('touchmove', (evt) => {
          if (!evt || !evt.isTrusted) return;
          lastTouchDown = dateNow();
          currentTouchDown = true;
          lastUserInteraction = lastTouchDown;
        }, passiveCapture);

        document.addEventListener('touchend', (evt) => {
          if (!evt || !evt.isTrusted) return;
          if (currentTouchDown) {
            lastTouchUp = dateNow();
            currentTouchDown = false;
            lastUserInteraction = lastTouchUp;
            delayFlushActiveItemsAfterUserActionK_ && delayFlushActiveItemsAfterUserActionK_();
          }
        }, passiveCapture);

        document.addEventListener('touchcancel', (evt) => {
          if (!evt || !evt.isTrusted) return;
          if (currentTouchDown) {
            lastTouchUp = dateNow();
            currentTouchDown = false;
            lastUserInteraction = lastTouchUp;
            delayFlushActiveItemsAfterUserActionK_ && delayFlushActiveItemsAfterUserActionK_();
          }
        }, passiveCapture);


      }


      const onRegistryReadyForDOMOperations = () => {
        let firstCheckedOnYtInit = false;

        const mightFirstCheckOnYtInit = () => {
          if (firstCheckedOnYtInit) return;
          firstCheckedOnYtInit = true;

          if (!document.body || !document.head) return;

          if (!assertor(() => location.pathname.startsWith('/live_chat') && location.search.indexOf('continuation=') >= 0)) return;

          addCssManaged();

          let efsContainer = document.getElementById('elzm-fonts-yk75g');
          if (efsContainer && efsContainer.parentNode !== document.body) {
            document.body.appendChild(efsContainer);
          }


        }

        if (!assertor(() => location.pathname.startsWith('/live_chat') && location.search.indexOf('continuation=') >= 0)) return;
        // if (!assertor(() => document.getElementById('yt-masthead') === null)) return; 

        if (document.documentElement && document.head) {

          addCssManaged();

        }
        // console.log(document.body===null)

        customElements.whenDefined('yt-live-chat-item-list-renderer').then(() => {


          const tag = "yt-live-chat-item-list-renderer"
          const dummy = document.createElement(tag);


          const cProto = getProto(dummy);
          if (!cProto || !cProto.attached) {
            console.warn(`proto.attached for ${tag} is unavailable.`);
            return;
          }


          mightFirstCheckOnYtInit();
          groupCollapsed("YouTube Super Fast Chat", " | yt-live-chat-item-list-renderer hacks");
          console.log("[Begin]");

          const mclp = cProto;
          try {
            assertor(() => typeof mclp.scrollToBottom_ === 'function');
            assertor(() => typeof mclp.flushActiveItems_ === 'function');
            assertor(() => typeof mclp.canScrollToBottom_ === 'function');
            assertor(() => typeof mclp.setAtBottom === 'function');
            assertor(() => typeof mclp.scrollToBottom66_ === 'undefined');
            assertor(() => typeof mclp.flushActiveItems66_ === 'undefined');
          } catch (e) { }


          try {
            assertor(() => typeof mclp.attached === 'function');
            assertor(() => typeof mclp.detached === 'function');
            assertor(() => typeof mclp.canScrollToBottom_ === 'function');
            assertor(() => typeof mclp.isSmoothScrollEnabled_ === 'function');
            assertor(() => typeof mclp.maybeResizeScrollContainer_ === 'function');
            assertor(() => typeof mclp.refreshOffsetContainerHeight_ === 'function');
            assertor(() => typeof mclp.smoothScroll_ === 'function');
            assertor(() => typeof mclp.resetSmoothScroll_ === 'function');
          } catch (e) { }

          mclp.__intermediate_delay__ = null;

          let mzk = 0;
          let myk = 0;
          let mlf = 0;
          let myw = 0;
          let mzt = 0;
          let zarr = null;
          let mlg = 0;

          if ((mclp.clearList || 0).length === 0) {
            assertor(() => fnIntegrity(mclp.clearList, '0.106.50'));
            mclp.clearList66 = mclp.clearList;
            mclp.clearList = function () {
              mzk++;
              myk++;
              mlf++;
              myw++;
              mzt++;
              mlg++;
              zarr = null;
              this.__intermediate_delay__ = null;
              this.clearList66();
            };
            console.log("clearList", "OK");
          } else {
            console.log("clearList", "NG");
          }


          let onListRendererAttachedDone = false;

          function setList(itemOffset, items) {

            const isFirstTime = onListRendererAttachedDone === false;

            if (isFirstTime) {
              onListRendererAttachedDone = true;
              Promise.resolve().then(watchUserCSS);
              addCssManaged();
              setupEvents();
            }

            setupStyle(itemOffset, items);

            setupMutObserver(items);
          }

          mclp.attached419 = async function () {

            if (!this.isAttached) return;

            let maxTrial = 16;
            while (!this.$ || !this.$['item-scroller'] || !this.$['item-offset'] || !this.$['items']) {
              if (--maxTrial < 0 || !this.isAttached) return;
              await new Promise(requestAnimationFrame);
            }

            if (this.isAttached !== true) return;

            if (!this.$) {
              console.warn("!this.$");
              return;
            }
            if (!this.$) return;
            /** @type {HTMLElement | null} */
            const itemScroller = this.$['item-scroller'];
            /** @type {HTMLElement | null} */
            const itemOffset = this.$['item-offset'];
            /** @type {HTMLElement | null} */
            const items = this.$['items'];

            if (!itemScroller || !itemOffset || !items) {
              console.warn("items.parentNode !== itemOffset");
              return;
            }

            if (nodeParent(items) !== itemOffset) {

              console.warn("items.parentNode !== itemOffset");
              return;
            }


            if (items.id !== 'items' || itemOffset.id !== "item-offset") {

              console.warn("id incorrect");
              return;
            }

            const isTargetItems = HTMLElement.prototype.matches.call(items, '#item-offset.style-scope.yt-live-chat-item-list-renderer > #items.style-scope.yt-live-chat-item-list-renderer')

            if (!isTargetItems) {
              console.warn("!isTargetItems");
              return;
            }

            setList(itemOffset, items);

          }

          mclp.attached331 = mclp.attached;
          mclp.attached = function () {
            this.attached419 && this.attached419();
            return this.attached331();
          }

          mclp.detached331 = mclp.detached;

          mclp.detached = function () {
            setupMutObserver();
            return this.detached331();
          }

          let t31_items = document.querySelector('#item-offset.style-scope.yt-live-chat-item-list-renderer > #items.style-scope.yt-live-chat-item-list-renderer');
          let t31_itemOffset = t31_items ? nodeParent(t31_items) : null;

          if (t31_items && t31_itemOffset) {
            setList(t31_itemOffset, t31_items);
          }

          if ((mclp.async || 0).length === 2 && (mclp.cancelAsync || 0).length === 1) {

            assertor(() => fnIntegrity(mclp.async, '2.24.15'));
            assertor(() => fnIntegrity(mclp.cancelAsync, '1.15.8'));

            /** @type {Map<number, any>} */
            const aMap = new Map();
            let count = 6150;
            mclp.async66 = mclp.async;
            mclp.async = function (e, f) {
              // ensure the previous operation is done
              // .async is usually after the time consuming functions like flushActiveItems_ and scrollToBottom_
              const hasF = arguments.length === 2;
              const stack = new Error().stack;
              const isFlushAsync = stack.indexOf('flushActiveItems_') >= 0;
              if (count > 1e9) count = 6159;
              const resId = ++count;
              aMap.set(resId, e);
              (this.__intermediate_delay__ || Promise.resolve()).then(rk => {
                const rp = aMap.get(resId);
                if (typeof rp !== 'function') {
                  return;
                }
                let cancelCall = false;
                if (isFlushAsync) {
                  if (rk < 0) {
                    cancelCall = true;
                  } else if (rk === 2 && arguments[0] === this.maybeScrollToBottom_) {
                    cancelCall = true;
                  }
                }
                if (cancelCall) {
                  aMap.delete(resId);
                } else {
                  const asyncEn = function () {
                    aMap.delete(resId);
                    return rp.apply(this, arguments);
                  };
                  aMap.set(resId, hasF ? this.async66(asyncEn, f) : this.async66(asyncEn));
                }
              });

              return resId;
            }

            mclp.cancelAsync66 = mclp.cancelAsync;
            mclp.cancelAsync = function (resId) {
              if (resId <= 6150) {
                this.cancelAsync66(resId);
              } else if (aMap.has(resId)) {
                const rp = aMap.get(resId);
                aMap.delete(resId);
                if (typeof rp !== 'function') {
                  this.cancelAsync66(rp);
                }
              }
            }

            console.log("async", "OK");
          } else {
            console.log("async", "NG");
          }


          if ((mclp.showNewItems_ || 0).length === 0 && ENABLE_NO_SMOOTH_TRANSFORM) {

            assertor(() => fnIntegrity(mclp.showNewItems_, '0.170.79'));
            mclp.showNewItems66_ = mclp.showNewItems_;

            mclp.showNewItems77_ = async function () {
              if (myk > 1e9) myk = 9;
              let tid = ++myk;

              await new Promise(requestAnimationFrame);

              if (tid !== myk) {
                return;
              }

              const cnt = this;

              await Promise.resolve();
              cnt.showNewItems66_();

              await Promise.resolve();

            }

            mclp.showNewItems_ = function () {

              const cnt = this;
              cnt.__intermediate_delay__ = new Promise(resolve => {
                cnt.showNewItems77_().then(() => {
                  resolve();
                });
              });
            }

            console.log("showNewItems_", "OK");
          } else {
            console.log("showNewItems_", "NG");
          }


          if ((mclp.flushActiveItems_ || 0).length === 0) {

            assertor(() => fnIntegrity(mclp.flushActiveItems_, '0.137.81'));

            let contensWillChangeController = null;

            mclp.flushActiveItems66_ = mclp.flushActiveItems_;

            mclp.flushActiveItems78_ = async function (tid) {
              try {
                const lockedMaxItemsToDisplay = this.data.maxItemsToDisplay944;
                let logger = false;
                const cnt = this;
                let immd = cnt.__intermediate_delay__;
                await new Promise(requestAnimationFrame);

                if (tid !== mlf || cnt.isAttached === false || (cnt.hostElement || cnt).isConnected === false) return;
                if (!cnt.activeItems_ || cnt.activeItems_.length === 0) return;

                mlf++;
                if (mlg > 1e9) mlg = 9;
                ++mlg;

                const tmpMaxItemsCount = this.data.maxItemsToDisplay;
                const reducedMaxItemsToDisplay = MAX_ITEMS_FOR_FULL_FLUSH;
                let changeMaxItemsToDisplay = false;
                const activeItemsLen = this.activeItems_.length;
                if (activeItemsLen > tmpMaxItemsCount && tmpMaxItemsCount > 0) {
                  logger = true;

                  groupCollapsed("YouTube Super Fast Chat", " | flushActiveItems78_");

                  logger && console.log('[Begin]')

                  console.log('this.activeItems_.length > N', activeItemsLen, tmpMaxItemsCount);
                  if (ENABLE_REDUCED_MAXITEMS_FOR_FLUSH && lockedMaxItemsToDisplay === tmpMaxItemsCount && lockedMaxItemsToDisplay !== reducedMaxItemsToDisplay) {
                    console.log('reduce maxitems');
                    if (tmpMaxItemsCount > reducedMaxItemsToDisplay) {
                      // as all the rendered chats are already "outdated"
                      // all old chats shall remove and reduced number of few chats will be rendered
                      // then restore to the original number
                      changeMaxItemsToDisplay = true;
                      this.data.maxItemsToDisplay = reducedMaxItemsToDisplay;
                      console.log(`'maxItemsToDisplay' is reduced from ${tmpMaxItemsCount} to ${reducedMaxItemsToDisplay}.`)
                    }
                    this.activeItems_.splice(0, activeItemsLen - this.data.maxItemsToDisplay);
                    //   console.log('changeMaxItemsToDisplay 01', this.data.maxItemsToDisplay, oMaxItemsToDisplay, reducedMaxItemsToDisplay)

                    console.log('new this.activeItems_.length > N', this.activeItems_.length);
                  } else {
                    this.activeItems_.splice(0, activeItemsLen - (tmpMaxItemsCount < 900 ? tmpMaxItemsCount : 900));

                    console.log('new this.activeItems_.length > N', this.activeItems_.length);
                  }
                }
                // it is found that it will render all stacked chats after switching back from background
                // to avoid lagging in popular livestream with massive chats, trim first before rendering.
                // this.activeItems_.length > this.data.maxItemsToDisplay && this.activeItems_.splice(0, this.activeItems_.length - this.data.maxItemsToDisplay);


                const items = (cnt.$ || 0).items;

                if (USE_WILL_CHANGE_CONTROLLER) {
                  if (contensWillChangeController && contensWillChangeController.element !== items) {
                    contensWillChangeController.release();
                    contensWillChangeController = null;
                  }
                  if (!contensWillChangeController) contensWillChangeController = new WillChangeController(items, 'contents');
                }
                const wcController = contensWillChangeController;
                cnt.__intermediate_delay__ = Promise.all([cnt.__intermediate_delay__ || null, immd || null]);
                wcController && wcController.beforeOper();
                await Promise.resolve();
                const len1 = cnt.activeItems_.length;
                cnt.flushActiveItems66_();
                const len2 = cnt.activeItems_.length;
                const bAsync = len1 !== len2;
                await Promise.resolve();
                if (wcController) {
                  if (bAsync) {
                    cnt.async(() => {
                      wcController.afterOper();
                    });
                  } else {
                    wcController.afterOper();
                  }
                }
                if (changeMaxItemsToDisplay && this.data.maxItemsToDisplay === reducedMaxItemsToDisplay && tmpMaxItemsCount > reducedMaxItemsToDisplay) {
                  this.data.maxItemsToDisplay = tmpMaxItemsCount;

                  logger && console.log(`'maxItemsToDisplay' is restored from ${reducedMaxItemsToDisplay} to ${tmpMaxItemsCount}.`);
                  //   console.log('changeMaxItemsToDisplay 02', this.data.maxItemsToDisplay, oMaxItemsToDisplay, reducedMaxItemsToDisplay)
                } else if (changeMaxItemsToDisplay) {

                  logger && console.log(`'maxItemsToDisplay' cannot be restored`, {
                    maxItemsToDisplay: this.data.maxItemsToDisplay,
                    reducedMaxItemsToDisplay,
                    originalMaxItemsToDisplay: tmpMaxItemsCount
                  });
                }
                logger && console.log('[End]')

                logger && console.groupEnd();

                if (!ENABLE_NO_SMOOTH_TRANSFORM) {


                  const ff = () => {

                    if (cnt.isAttached === false || (cnt.hostElement || cnt).isConnected === false) return;
                    //   if (tid !== mlf || cnt.isAttached === false || (cnt.hostElement || cnt).isConnected === false) return;
                    if (!cnt.atBottom && cnt.allowScroll && cnt.hasUserJustInteracted11_ && !cnt.hasUserJustInteracted11_()) {
                      cnt.scrollToBottom_();

                      Promise.resolve().then(() => {

                        if (cnt.isAttached === false || (cnt.hostElement || cnt).isConnected === false) return;
                        if (!cnt.canScrollToBottom_()) cnt.scrollToBottom_();
                      });


                    }
                  }

                  ff();


                  Promise.resolve().then(ff);

                  // requestAnimationFrame(ff);
                } else if (true) { // it might not be sticky to bottom when there is a full refresh.

                  const knt = cnt;
                  if (!scrollChatFn) {
                    const cnt = knt;
                    const f = () => {
                      const itemScroller = cnt.itemScroller;
                      if (!itemScroller || itemScroller.isConnected === false || cnt.isAttached === false) return;
                      if (!cnt.atBottom) {
                        cnt.scrollToBottom_();
                      } else if (itemScroller.scrollTop === 0) { // not yet interacted by user; cannot stick to bottom
                        itemScroller.scrollTop = itemScroller.scrollHeight;
                      }
                    };
                    scrollChatFn = () => Promise.resolve().then(f).then(f);
                  }

                  if (!ENABLE_FULL_RENDER_REQUIRED) scrollChatFn();
                }

                return 1;


              } catch (e) {
                console.warn(e);
              }
            }

            mclp.flushActiveItems77_ = async function () {
              try {

                const cnt = this;
                if (mlf > 1e9) mlf = 9;
                let tid = ++mlf;
                if (tid !== mlf || cnt.isAttached === false || (cnt.hostElement || cnt).isConnected === false) return;
                if (!cnt.activeItems_ || cnt.activeItems_.length === 0) return;

                // 4 times to maxItems to avoid frequent trimming.
                // 1 ... 10 ... 20 ... 30 ... 40 ... 50 ... 60 => 16 ... 20 ... 30 ..... 60 ... => 16

                const lockedMaxItemsToDisplay = this.data.maxItemsToDisplay944;
                this.activeItems_.length > lockedMaxItemsToDisplay * 4 && lockedMaxItemsToDisplay > 4 && this.activeItems_.splice(0, this.activeItems_.length - lockedMaxItemsToDisplay - 1);
                if (cnt.canScrollToBottom_()) {
                  if (cnt.mutexPromiseFA77) await cnt.mutexPromiseFA77;
                  if (tid !== mlf) return;
                  let qResolve = null;
                  cnt.mutexPromiseFA77 = new Promise(resolve => { qResolve = resolve; })
                  let res;
                  try {
                    res = await cnt.flushActiveItems78_(tid);
                  } catch (e) {
                    console.warn(e);
                  }
                  qResolve && qResolve();
                  return res;
                } else {
                  // cnt.flushActiveItems66_();
                  // this.activeItems_.length > this.data.maxItemsToDisplay && this.activeItems_.splice(0, this.activeItems_.length - this.data.maxItemsToDisplay);
                  return 2;
                }
              } catch (e) {
                console.warn(e);
              }
            }

            mclp.flushActiveItems_ = function () {
              const cnt = this;

              if (arguments.length !== 0 || !cnt.activeItems_ || !cnt.canScrollToBottom_) return cnt.flushActiveItems66_.apply(this, arguments);

              if (cnt.activeItems_.length === 0) {
                cnt.__intermediate_delay__ = null;
                return;
              }

              const cntData = ((cnt || 0).data || 0);
              if (cntData.maxItemsToDisplay944 === undefined) {
                cntData.maxItemsToDisplay944 = null;
                if (cntData.maxItemsToDisplay > MAX_ITEMS_FOR_TOTAL_DISPLAY) cntData.maxItemsToDisplay = MAX_ITEMS_FOR_TOTAL_DISPLAY;
                cntData.maxItemsToDisplay944 = cntData.maxItemsToDisplay || null;
              }

              // ignore previous __intermediate_delay__ and create a new one
              cnt.__intermediate_delay__ = new Promise(resolve => {
                cnt.flushActiveItems77_().then(rt => {
                  if (rt === 1) resolve(1); // success, scroll to bottom
                  else if (rt === 2) resolve(2); // success, trim
                  else resolve(-1); // skip
                });
              });

            }
            console.log("flushActiveItems_", "OK");
          } else {
            console.log("flushActiveItems_", "NG");
          }

          mclp.delayFlushActiveItemsAfterUserAction11_ = async function () {
            try {
              if (mlg > 1e9) mlg = 9;
              const tid = ++mlg;
              const keepTrialCond = () => this.atBottom && this.allowScroll && (tid === mlg) && this.isAttached === true && this.activeItems_.length >= 1 && (this.hostElement || 0).isConnected === true;
              const runCond = () => this.canScrollToBottom_();
              if (!keepTrialCond()) return;
              if (runCond()) return this.flushActiveItems_() | 1; // avoid return promise
              await new Promise(r => setTimeout(r, 80));
              if (!keepTrialCond()) return;
              if (runCond()) return this.flushActiveItems_() | 1;
              await new Promise(requestAnimationFrame);
              if (runCond()) return this.flushActiveItems_() | 1;
            } catch (e) {
              console.warn(e);
            }
          }

          if ((mclp.atBottomChanged_ || 0).length === 1) {
            // note: if the scrolling is too frequent, the show more visibility might get wrong.
            assertor(() => fnIntegrity(mclp.atBottomChanged_, '1.75.39'));

            const querySelector = HTMLElement.prototype.querySelector;
            const U = (element) => ({
              querySelector: (selector) => querySelector.call(element, selector)
            });

            let qid = 0;
            mclp.atBottomChanged_ = function (a) {
              let tid = ++qid;
              var b = this;
              a ? this.hideShowMoreAsync_ || (this.hideShowMoreAsync_ = this.async(function () {
                if (tid !== qid) return;
                U(b.hostElement).querySelector("#show-more").style.visibility = "hidden"
              }, 200)) : (this.hideShowMoreAsync_ && this.cancelAsync(this.hideShowMoreAsync_),
                this.hideShowMoreAsync_ = null,
                U(this.hostElement).querySelector("#show-more").style.visibility = "visible")
            }

            console.log("atBottomChanged_", "OK");
          } else {
            console.log("atBottomChanged_", "NG");
          }

          if ((mclp.onScrollItems_ || 0).length === 1) {

            assertor(() => fnIntegrity(mclp.onScrollItems_, '1.17.9'));
            mclp.onScrollItems66_ = mclp.onScrollItems_;
            mclp.onScrollItems77_ = async function (evt) {
              if (myw > 1e9) myw = 9;
              let tid = ++myw;

              await new Promise(requestAnimationFrame);

              if (tid !== myw) {
                return;
              }

              const cnt = this;

              await Promise.resolve();
              if (USE_OPTIMIZED_ON_SCROLL_ITEMS) {
                await Promise.resolve().then(() => {
                  this.ytRendererBehavior.onScroll(evt);
                }).then(() => {
                  if (this.canScrollToBottom_()) {
                    const hasUserJustInteracted = this.hasUserJustInteracted11_ ? this.hasUserJustInteracted11_() : true;
                    if (hasUserJustInteracted) {
                      // only when there is an user action
                      this.setAtBottom();
                      return 1;
                    }
                  } else {
                    // no message inserting
                    this.setAtBottom();
                    return 1;
                  }
                }).then((r) => {

                  if (this.activeItems_.length) {

                    if (this.canScrollToBottom_()) {
                      this.flushActiveItems_();
                      return 1 && r;
                    } else if (this.atBottom && this.allowScroll && (this.hasUserJustInteracted11_ && this.hasUserJustInteracted11_())) {
                      // delayed due to user action
                      this.delayFlushActiveItemsAfterUserAction11_ && this.delayFlushActiveItemsAfterUserAction11_();
                      return 0;
                    }
                  }
                }).then((r) => {
                  if (r) {
                    // ensure setAtBottom is correctly set
                    this.setAtBottom();
                  }
                });
              } else {
                cnt.onScrollItems66_(evt);
              }

              await Promise.resolve();

            }

            mclp.onScrollItems_ = function (evt) {

              const cnt = this;
              cnt.__intermediate_delay__ = new Promise(resolve => {
                cnt.onScrollItems77_(evt).then(() => {
                  resolve();
                });
              });
            }
            console.log("onScrollItems_", "OK");
          } else {
            console.log("onScrollItems_", "NG");
          }

          if ((mclp.handleLiveChatActions_ || 0).length === 1) {

            assertor(() => fnIntegrity(mclp.handleLiveChatActions_, '1.31.17'));
            mclp.handleLiveChatActions66_ = mclp.handleLiveChatActions_;

            mclp.handleLiveChatActions77_ = async function (arr) {
              if (typeof (arr || 0).length !== 'number') {
                this.handleLiveChatActions66_(arr);
                return;
              }
              if (mzt > 1e9) mzt = 9;
              let tid = ++mzt;

              if (zarr === null) zarr = arr;
              else Array.prototype.push.apply(zarr, arr);
              arr = null;

              await new Promise(requestAnimationFrame);

              if (tid !== mzt || zarr === null) {
                return;
              }

              const carr = zarr;
              zarr = null;

              await Promise.resolve();
              this.handleLiveChatActions66_(carr);
              await Promise.resolve();

            }

            mclp.handleLiveChatActions_ = function (arr) {

              const cnt = this;
              cnt.__intermediate_delay__ = new Promise(resolve => {
                cnt.handleLiveChatActions77_(arr).then(() => {
                  resolve();
                });
              });
            }
            console.log("handleLiveChatActions_", "OK");
          } else {
            console.log("handleLiveChatActions_", "NG");
          }

          mclp.hasUserJustInteracted11_ = () => {
            const t = dateNow();
            return (t - lastWheel < 80) || currentMouseDown || currentTouchDown || (t - lastUserInteraction < 80);
          }

          if ((mclp.canScrollToBottom_ || 0).length === 0) {

            assertor(() => fnIntegrity(mclp.canScrollToBottom_, '0.9.5'));

            mclp.canScrollToBottom_ = function () {
              return this.atBottom && this.allowScroll && !this.hasUserJustInteracted11_();
            }

            console.log("canScrollToBottom_", "OK");
          } else {
            console.log("canScrollToBottom_", "NG");
          }

          if (ENABLE_NO_SMOOTH_TRANSFORM) {

            mclp.isSmoothScrollEnabled_ = function () {
              return false;
            }

            mclp.maybeResizeScrollContainer_ = function () {
              //
            }

            mclp.refreshOffsetContainerHeight_ = function () {
              //
            }

            mclp.smoothScroll_ = function () {
              //
            }

            mclp.resetSmoothScroll_ = function () {
              //
            }
            console.log("ENABLE_NO_SMOOTH_TRANSFORM", "OK");
          } else {
            console.log("ENABLE_NO_SMOOTH_TRANSFORM", "NG");
          }

          console.log("[End]");
          console.groupEnd();

        });


        const tickerContainerSetAttribute = function (attrName, attrValue) { // ensure '14.30000001%'.toFixed(1)

          let yd = (this.__dataHost || (this.inst || 0).__dataHost || 0).__data;

          if (arguments.length === 2 && attrName === 'style' && yd && attrValue) {

            // let v = yd.containerStyle.privateDoNotAccessOrElseSafeStyleWrappedValue_;
            let v = `${attrValue}`;
            // conside a ticker is 101px width
            // 1% = 1.01px
            // 0.2% = 0.202px


            const ratio1 = (yd.ratio * 100);
            if (ratio1 > -1) { // avoid NaN

              // countdownDurationMs
              // 600000 - 0.2%    <1% = 6s>  <0.2% = 1.2s>
              // 300000 - 0.5%    <1% = 3s>  <0.5% = 1.5s>
              // 150000 - 1%    <1% = 1.5s>
              // 75000 - 2%    <1% =0.75s > <2% = 1.5s>
              // 30000 - 5%    <1% =0.3s > <5% = 1.5s>

              // 99px * 5% = 4.95px

              // 15000 - 10%    <1% =0.15s > <10% = 1.5s>


              // 1% Duration

              let ratio2 = ratio1;

              const ydd = yd.data;
              const d1 = ydd.durationSec;
              const d2 = ydd.fullDurationSec;

              if (d1 === d2 && d1 > 1) {

                if (d1 > 400) ratio2 = Math.round(ratio2 * 5) / 5; // 0.2%
                else if (d1 > 200) ratio2 = Math.round(ratio2 * 2) / 2; // 0.5%
                else if (d1 > 100) ratio2 = Math.round(ratio2 * 1) / 1; // 1%
                else if (d1 > 50) ratio2 = Math.round(ratio2 * 0.5) / 0.5; // 2%
                else if (d1 > 25) ratio2 = Math.round(ratio2 * 0.2) / 0.2; // 5% (max => 99px * 5% = 4.95px)
                else ratio2 = Math.round(ratio2 * 0.2) / 0.2;

              } else {
                ratio2 = Math.round(ratio2 * 5) / 5; // 0.2% (min)
              }

              // ratio2 = Math.round(ratio2 * 5) / 5;
              ratio2 = ratio2.toFixed(1);
              v = v.replace(`${ratio1}%`, `${ratio2}%`).replace(`${ratio1}%`, `${ratio2}%`);

              if (yd.__style_last__ === v) return;
              yd.__style_last__ = v;
              // do not consider any delay here.
              // it shall be inside the looping for all properties changes. all the css background ops are in the same microtask.

            }

            HTMLElement.prototype.setAttribute.call(dr(this), attrName, v);


          } else {
            HTMLElement.prototype.setAttribute.apply(dr(this), arguments);
          }

        };


        const fpTicker = (renderer) => {
          const cnt = renderer.inst || renderer;
          assertor(() => typeof (cnt || 0).is === 'string');
          assertor(() => ((cnt || 0).hostElement || 0).nodeType === 1);
          const container = (cnt.$ || 0).container;
          if (container) {
            assertor(() => (container || 0).nodeType === 1);
            assertor(() => typeof container.setAttribute === 'function');
            container.setAttribute = tickerContainerSetAttribute;
          } else {
            console.warn(`"container" does not exist in ${cnt.is}`);
          }
        };

        const tags = ["yt-live-chat-ticker-paid-message-item-renderer", "yt-live-chat-ticker-paid-sticker-item-renderer",
          "yt-live-chat-ticker-renderer", "yt-live-chat-ticker-sponsor-item-renderer"];


        Promise.all(tags.map(tag => customElements.whenDefined(tag))).then(() => {

          mightFirstCheckOnYtInit();
          groupCollapsed("YouTube Super Fast Chat", " | yt-live-chat-ticker-... hacks");
          console.log("[Begin]");

          for (const tag of tags) {
            const dummy = document.createElement(tag);

            const cProto = getProto(dummy);
            if (!cProto || !cProto.attached) {
              console.warn(`proto.attached for ${tag} is unavailable.`);
              continue;
            }

            cProto.attached77 = cProto.attached;

            cProto.attached = function () {
              fpTicker(this.hostElement || this);
              return this.attached77();
            }

            for (const elm of document.getElementsByTagName(tag)) {
              fpTicker(elm);
            }

            if (ENABLE_RAF_HACK_TICKERS && rafHub !== null) {

              // cancelable - this.rafId < isAnimationPausedChanged >

              let doHack = false;

              if (typeof cProto.startCountdown === 'function' && typeof cProto.updateTimeout === 'function' && typeof cProto.isAnimationPausedChanged === 'function') {

                console.log('startCountdown', typeof cProto.startCountdown)
                console.log('updateTimeout', typeof cProto.updateTimeout)
                console.log('isAnimationPausedChanged', typeof cProto.isAnimationPausedChanged)

                doHack = fnIntegrity(cProto.startCountdown, '2.66.37') && fnIntegrity(cProto.updateTimeout, '1.76.45') && fnIntegrity(cProto.isAnimationPausedChanged, '2.56.30')

              }
              if (doHack) {

                cProto.startCountdown = function (a, b) {
                  // console.log('cProto.startCountdown', tag) // yt-live-chat-ticker-sponsor-item-renderer
                  if (!this.boundUpdateTimeout37_) this.boundUpdateTimeout37_ = this.updateTimeout.bind(this);
                  b = void 0 === b ? 0 : b;
                  void 0 !== a && (this.countdownMs = 1E3 * a,
                    this.countdownDurationMs = b ? 1E3 * b : this.countdownMs,
                    this.ratio = 1,
                    this.lastCountdownTimeMs || this.isAnimationPaused || (this.lastCountdownTimeMs = performance.now(),
                      this.rafId = rafHub.request(this.boundUpdateTimeout37_)))
                };

                cProto.updateTimeout = function (a) {
                  // console.log('cProto.updateTimeout', tag) // yt-live-chat-ticker-sponsor-item-renderer
                  if (!this.boundUpdateTimeout37_) this.boundUpdateTimeout37_ = this.updateTimeout.bind(this);
                  this.countdownMs = Math.max(0, this.countdownMs - (a - (this.lastCountdownTimeMs || 0)));
                  this.ratio = this.countdownMs / this.countdownDurationMs;
                  this.isAttached && this.countdownMs ? (this.lastCountdownTimeMs = a,
                    this.rafId = rafHub.request(this.boundUpdateTimeout37_)) : (this.lastCountdownTimeMs = null,
                      this.isAttached && ("auto" === this.hostElement.style.width && this.setContainerWidth(),
                        this.slideDown()))
                };

                cProto.isAnimationPausedChanged = function (a, b) {
                  if (!this.boundUpdateTimeout37_) this.boundUpdateTimeout37_ = this.updateTimeout.bind(this);
                  a ? rafHub.cancel(this.rafId) : !a && b && (a = this.lastCountdownTimeMs || 0,
                    this.detlaSincePausedSecs && (a = (this.lastCountdownTimeMs || 0) + 1E3 * this.detlaSincePausedSecs,
                      this.detlaSincePausedSecs = 0),
                    this.boundUpdateTimeout37_(a),
                    this.lastCountdownTimeMs = window.performance.now())
                };

                console.log('RAF_HACK_TICKERS', tag, "OK")
              } else if (tag === 'yt-live-chat-ticker-renderer') {

                // no timer function to be set on yt-live-chat-ticker-renderer

              } else {

                console.log('RAF_HACK_TICKERS', tag, "NG")
              }

            }

          }
          console.log("[End]");
          console.groupEnd();


        })


        if (ENABLE_RAF_HACK_INPUT_RENDERER && rafHub !== null) {


          customElements.whenDefined("yt-live-chat-message-input-renderer").then(() => {

            mightFirstCheckOnYtInit();
            groupCollapsed("YouTube Super Fast Chat", " | yt-live-chat-message-input-renderer hacks");
            console.log("[Begin]");
            (() => {

              const tag = "yt-live-chat-message-input-renderer"
              const dummy = document.createElement(tag);

              const cProto = getProto(dummy);
              if (!cProto || !cProto.attached) {
                console.warn(`proto.attached for ${tag} is unavailable.`);
                return;
              }

              let doHack = false;
              if (typeof cProto.handleTimeout === 'function' && typeof cProto.updateTimeout === 'function') {

                // not cancellable
                console.log('handleTimeout', typeof cProto.handleTimeout)
                console.log('updateTimeout', typeof cProto.updateTimeout)

                doHack = fnIntegrity(cProto.handleTimeout, '1.27.16') && fnIntegrity(cProto.updateTimeout, '1.50.33');

              }

              if (doHack) {

                cProto.handleTimeout = function (a) {
                  console.log('cProto.handleTimeout', tag)
                  if (!this.boundUpdateTimeout38_) this.boundUpdateTimeout38_ = this.updateTimeout.bind(this);
                  this.timeoutDurationMs = this.timeoutMs = a;
                  this.countdownRatio = 1;
                  0 === this.lastTimeoutTimeMs && rafHub.request(this.boundUpdateTimeout38_)
                };
                cProto.updateTimeout = function (a) {
                  console.log('cProto.updateTimeout', tag)
                  if (!this.boundUpdateTimeout38_) this.boundUpdateTimeout38_ = this.updateTimeout.bind(this);
                  this.lastTimeoutTimeMs && (this.timeoutMs = Math.max(0, this.timeoutMs - (a - this.lastTimeoutTimeMs)),
                    this.countdownRatio = this.timeoutMs / this.timeoutDurationMs);
                  this.isAttached && this.timeoutMs ? (this.lastTimeoutTimeMs = a,
                    rafHub.request(this.boundUpdateTimeout38_)) : this.lastTimeoutTimeMs = 0
                };

                console.log('RAF_HACK_INPUT_RENDERER', tag, "OK")
              } else {

                console.log('RAF_HACK_INPUT_RENDERER', tag, "NG")
              }

            })();

            console.log("[End]");

            console.groupEnd();


          })


        }

        if (ENABLE_RAF_HACK_EMOJI_PICKER && rafHub !== null) {


          customElements.whenDefined("yt-emoji-picker-renderer").then(() => {

            mightFirstCheckOnYtInit();
            groupCollapsed("YouTube Super Fast Chat", " | yt-emoji-picker-renderer hacks");
            console.log("[Begin]");
            (() => {

              const tag = "yt-emoji-picker-renderer"
              const dummy = document.createElement(tag);

              const cProto = getProto(dummy);
              if (!cProto || !cProto.attached) {
                console.warn(`proto.attached for ${tag} is unavailable.`);
                return;
              }

              let doHack = false;
              if (typeof cProto.animateScroll_ === 'function') {

                // not cancellable
                console.log('animateScroll_', typeof cProto.animateScroll_)

                doHack = fnIntegrity(cProto.animateScroll_, '1.102.49')

              }

              if (doHack) {

                const querySelector = HTMLElement.prototype.querySelector;
                const U = (element) => ({
                  querySelector: (selector) => querySelector.call(element, selector)
                });

                cProto.animateScroll_ = function (a) {
                  // console.log('cProto.animateScroll_', tag) // yt-emoji-picker-renderer
                  if (!this.boundAnimateScroll39_) this.boundAnimateScroll39_ = this.animateScroll_.bind(this);
                  this.lastAnimationTime_ || (this.lastAnimationTime_ = a);
                  a -= this.lastAnimationTime_;
                  200 > a ? (U(this.hostElement).querySelector("#categories").scrollTop = this.animationStart_ + (this.animationEnd_ - this.animationStart_) * a / 200,
                    rafHub.request(this.boundAnimateScroll39_)) : (null != this.animationEnd_ && (U(this.hostElement).querySelector("#categories").scrollTop = this.animationEnd_),
                      this.animationEnd_ = this.animationStart_ = null,
                      this.lastAnimationTime_ = 0);
                  this.updateButtons_()
                }

                console.log('ENABLE_RAF_HACK_EMOJI_PICKER', tag, "OK")
              } else {

                console.log('ENABLE_RAF_HACK_EMOJI_PICKER', tag, "NG")
              }

            })();

            console.log("[End]");

            console.groupEnd();
          });
        }

        if (ENABLE_RAF_HACK_DOCKED_MESSAGE && rafHub !== null) {


          customElements.whenDefined("yt-live-chat-docked-message").then(() => {

            mightFirstCheckOnYtInit();
            groupCollapsed("YouTube Super Fast Chat", " | yt-live-chat-docked-message hacks");
            console.log("[Begin]");
            (() => {

              const tag = "yt-live-chat-docked-message"
              const dummy = document.createElement(tag);

              const cProto = getProto(dummy);
              if (!cProto || !cProto.attached) {
                console.warn(`proto.attached for ${tag} is unavailable.`);
                return;
              }

              let doHack = false;
              if (typeof cProto.detached === 'function' && typeof cProto.checkIntersections === 'function' && typeof cProto.onDockableMessagesChanged === 'function' && typeof cProto.boundCheckIntersections === 'undefined') {

                // cancelable - this.intersectRAF <detached>
                // yt-live-chat-docked-message
                // boundCheckIntersections <-> checkIntersections
                // onDockableMessagesChanged
                //  this.intersectRAF = window.requestAnimationFrame(this.boundCheckIntersections);

                console.log('detached', typeof cProto.detached)
                console.log('checkIntersections', typeof cProto.checkIntersections)
                console.log('onDockableMessagesChanged', typeof cProto.onDockableMessagesChanged)

                doHack = fnIntegrity(cProto.detached, '0.32.22') && fnIntegrity(cProto.checkIntersections, '0.128.85') && fnIntegrity(cProto.onDockableMessagesChanged, '0.20.11')

              }

              if (doHack) {

                cProto.checkIntersections = function () {
                  console.log('cProto.checkIntersections', tag)
                  if (this.dockableMessages.length) {
                    this.intersectRAF = rafHub.request(this.boundCheckIntersections);
                    var a = this.dockableMessages[0]
                      , b = this.hostElement.getBoundingClientRect();
                    a = a.getBoundingClientRect();
                    var c = a.top - b.top
                      , d = 8 >= c;
                    c = 8 >= c - this.hostElement.clientHeight;
                    if (d) {
                      for (var e; d;) {
                        e = this.dockableMessages.shift();
                        d = this.dockableMessages[0];
                        if (!d)
                          break;
                        d = d.getBoundingClientRect();
                        c = d.top - b.top;
                        var f = 8 >= c;
                        if (8 >= c - a.height)
                          if (f)
                            a = d;
                          else
                            return;
                        d = f
                      }
                      this.dock(e)
                    } else
                      c && this.dockedItem && this.clear()
                  } else
                    this.intersectRAF = 0
                }

                cProto.onDockableMessagesChanged = function () {
                  // console.log('cProto.onDockableMessagesChanged', tag) // yt-live-chat-docked-message
                  this.dockableMessages.length && !this.intersectRAF && (this.intersectRAF = rafHub.request(this.boundCheckIntersections))
                }

                cProto.detached = function () {
                  this.intersectRAF && rafHub.cancel(this.intersectRAF)
                }

                console.log('ENABLE_RAF_HACK_DOCKED_MESSAGE', tag, "OK")
              } else {

                console.log('ENABLE_RAF_HACK_DOCKED_MESSAGE', tag, "NG")
              }

            })();

            console.log("[End]");

            console.groupEnd();

          });

        }


      }

      customYtElements.onRegistryReady(onRegistryReadyForDOMOperations);


    })();


  });

})({ IntersectionObserver });

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