Adjust EXPERIMENT_FLAGS
// ==UserScript==
// @name YouTube EXPERIMENT_FLAGS Tamer (Basic)
// @namespace UserScripts
// @match https://www.youtube.com/*
// @version 0.4.8.100
// @license MIT
// @author CY Fung
// @icon https://raw.githubusercontent.com/cyfung1031/userscript-supports/main/icons/yt-engine.png
// @description Adjust EXPERIMENT_FLAGS
// @grant none
// @unwrap
// @run-at document-start
// @allFrames true
// @inject-into page
// ==/UserScript==
((__CONTEXT__) => {
// Purpose 1: Remove Obsolete Flags
// Purpose 2: Remove Flags bring no visual difference
// Purpose 3: Enable Flags bring performance boost
const DISABLE_CINEMATICS = false; // standard design
const NO_SerializedExperiment = true;
const KEEP_PLAYER_QUALITY_STICKY = true; // see https://greasyfork.org/scripts/471033/
const DISABLE_serializedExperimentIds = true;
const DISABLE_serializedExperimentFlags = true;
// const ALLOW_FLAGS_202404_flags11 = new Set([
// // 'use_core_sm',
// // 'use_new_cml',
// // 'web_api_url',
// ]);
const ENABLE_EXPERIMENT_FLAGS_MAINTAIN_STABLE_LIST = {
defaultValue: true, // performance boost
useExternal: () => typeof localStorage.EXPERIMENT_FLAGS_MAINTAIN_STABLE_LIST !== 'undefined',
externalValue: () => (+localStorage.EXPERIMENT_FLAGS_MAINTAIN_STABLE_LIST ? true : false)
};
const ENABLE_EXPERIMENT_FLAGS_MAINTAIN_REUSE_COMPONENTS = {
defaultValue: true, // not sure
useExternal: () => typeof localStorage.EXPERIMENT_FLAGS_MAINTAIN_REUSE_COMPONENTS !== 'undefined',
externalValue: () => (+localStorage.EXPERIMENT_FLAGS_MAINTAIN_REUSE_COMPONENTS ? true : false)
};
const ENABLE_EXPERIMENT_FLAGS_DEFER_DETACH = {
defaultValue: true, // not sure
useExternal: () => typeof localStorage.ENABLE_EXPERIMENT_FLAGS_DEFER_DETACH !== 'undefined',
externalValue: () => (+localStorage.ENABLE_EXPERIMENT_FLAGS_DEFER_DETACH ? true : false)
};
const ALLOW_ALL_LIVE_CHATS_FLAGS = true;
// TBC
// kevlar_tuner_should_always_use_device_pixel_ratio
// kevlar_tuner_should_clamp_device_pixel_ratio
// kevlar_tuner_clamp_device_pixel_ratio
// kevlar_tuner_should_use_thumbnail_factor
// kevlar_tuner_thumbnail_factor
// kevlar_tuner_min_thumbnail_quality
// kevlar_tuner_max_thumbnail_quality
// kevlar_tuner_should_test_visibility_time_between_jobs
// kevlar_tuner_visibility_time_between_jobs_ms
// kevlar_tuner_default_comments_delay
// kevlar_tuner_run_default_comments_delay
let settled = null;
// cinematic feature is no longer an experimential feature.
// It has been officially implemented.
// To disable cinematics, the user shall use other userscripts or just turn off the option in the video options.
const getSettingValue = (fm) => fm.useExternal() ? fm.externalValue() : fm.defaultValue;
const win = this instanceof Window ? this : window;
// Create a unique key for the script and check if it is already running
const hkey_script = 'jmimcvowrlzl';
if (win[hkey_script]) throw new Error('Duplicated Userscript Calling'); // avoid duplicated scripting
win[hkey_script] = true;
/** @type {globalThis.PromiseConstructor} */
const Promise = ((async () => { })()).constructor;
let isMainWindow = false;
let mzFlagDetected = new Set();
let zPlayerKevlar = false;
try {
isMainWindow = window.document === window.top.document
} catch (e) { }
function fixSerializedExperiment(conf) {
if (DISABLE_serializedExperimentIds && typeof conf.serializedExperimentIds === 'string') {
let ids = conf.serializedExperimentIds.split(',');
let newIds = [];
for (const id of ids) {
let keep = false;
if (keep) {
newIds.push(id);
}
}
conf.serializedExperimentIds = newIds.join(',');
}
if (DISABLE_serializedExperimentFlags && typeof conf.serializedExperimentFlags === 'string') {
const fg = conf.serializedExperimentFlags;
const rx = /(^|&)(\w+)=([^=&|\s\{\}\[\]\(\)?]*)/g;
let res = [];
for (let m; m = rx.exec(fg);) {
let key = m[2];
let value = m[3];
let keep = false;
if (KEEP_PLAYER_QUALITY_STICKY) {
if (key === 'html5_exponential_memory_for_sticky' || key.startsWith('h5_expr_')) {
keep = true;
}
}
if (!DISABLE_CINEMATICS) {
if (key === 'web_cinematic_watch_settings') {
keep = true;
}
}
if (keep) res.push(`${key}=${value}`);
}
conf.serializedExperimentFlags = res.join('&');
}
}
const cachedSetFn=(o) => {
const { use_maintain_stable_list, use_maintain_reuse_components, use_defer_detach } = o;
const BY_PASS = [
'enable_profile_cards_on_comments',
'suppress_error_204_logging',
...(!DISABLE_CINEMATICS ? [
'kevlar_measure_ambient_mode_idle',
'kevlar_watch_cinematics_invisible',
'web_cinematic_theater_mode',
'web_cinematic_fullscreen',
'enable_cinematic_blur_desktop_loading',
'kevlar_watch_cinematics',
'web_cinematic_masthead',
'web_watch_cinematics_preferred_reduced_motion_default_disabled'
] : []),
'live_chat_web_enable_command_handler',
'live_chat_channel_activity',
'live_chat_web_input_update',
...(ALLOW_ALL_LIVE_CHATS_FLAGS ? [
'live_chat_banner_expansion_fix',
'live_chat_enable_mod_view',
'live_chat_enable_qna_banner_overflow_menu_actions',
'live_chat_enable_qna_channel',
'live_chat_enable_send_button_in_slow_mode',
'live_chat_filter_emoji_suggestions',
'live_chat_increased_min_height',
'live_chat_over_playlist',
'live_chat_web_use_emoji_manager_singleton',
'live_chat_whole_message_clickable',
'live_chat_emoji_picker_toggle_state',
'live_chat_enable_command_handler_resolver_map',
'live_chat_enable_controller_extraction',
'live_chat_enable_rta_manager',
'live_chat_require_space_for_autocomplete_emoji',
'live_chat_unclickable_message',
]:[]),
'kevlar_rendererstamper_event_listener', // https://github.com/cyfung1031/userscript-supports/issues/11
// kevlar_enable_up_arrow - no use
// kevlar_help_use_locale - might use
// kevlar_refresh_gesture - might use
// kevlar_smart_downloads - might use
// kevlar_thumbnail_fluid
'kevlar_ytb_live_badges',
...(!use_maintain_stable_list ? [
'kevlar_tuner_should_test_maintain_stable_list',
'kevlar_should_maintain_stable_list',
'kevlar_tuner_should_maintain_stable_list', // fallback
] : []),
...(!use_maintain_reuse_components ? [
'kevlar_tuner_should_test_reuse_components',
'kevlar_tuner_should_reuse_components',
'kevlar_should_reuse_components' // fallback
] : []),
'kevlar_system_icons',
// 'kevlar_prefetch_data_augments_network_data' continue;
// home page / watch page icons
'kevlar_three_dot_ink',
'kevlar_use_wil_icons',
'kevlar_home_skeleton',
'kevlar_fluid_touch_scroll',
'kevlar_watch_color_update',
'kevlar_use_vimio_behavior', // home page - channel icon
// collapsed meta; no teaser, use latest collapsed meta design
'kevlar_structured_description_content_inline',
'kevlar_watch_metadata_refresh',
'kevlar_watch_js_panel_height', // affect Tabview Youtube
'shorts_desktop_watch_while_p2',
'web_button_rework',
'web_darker_dark_theme_live_chat',
'web_darker_dark_theme', // it also affect cinemtaics
// modern menu
'web_button_rework_with_live',
'web_fix_fine_scrubbing_drag',
// full screen -buggy
'external_fullscreen',
// minimize menu
'web_modern_buttons',
'web_modern_dialogs',
// Tabview Youtube - multiline transcript
'enable_mixed_direction_formatted_strings'
];
const s = new Set(BY_PASS);
return s;
};
let cachedSet = null;
const hLooper = ((fn) => {
let nativeFnLoaded = false;
let kc1 = 0;
const setIntervalW = setInterval;
const clearIntervalW = clearInterval;
let microDisconnectFn = null;
let fStopLooper = false;
const looperFn = () => {
if (fStopLooper) return;
let config_ = null;
let EXPERIMENT_FLAGS = null;
try {
config_ = yt.config_;
EXPERIMENT_FLAGS = config_.EXPERIMENT_FLAGS
} catch (e) { }
if (EXPERIMENT_FLAGS) {
fn(EXPERIMENT_FLAGS, config_);
if (microDisconnectFn) {
let isYtLoaded = false;
try {
isYtLoaded = typeof ytcfg.set === 'function';
} catch (e) { }
if (isYtLoaded) {
microDisconnectFn();
}
}
}
let playerKevlar = null;
try {
playerKevlar = ytcfg.data_.WEB_PLAYER_CONTEXT_CONFIGS.WEB_PLAYER_CONTEXT_CONFIG_ID_KEVLAR_WATCH;
} catch (e) { }
if (playerKevlar && !zPlayerKevlar) {
zPlayerKevlar = true;
if (NO_SerializedExperiment && typeof playerKevlar.serializedExperimentFlags === 'string' && typeof playerKevlar.serializedExperimentIds === 'string') {
fixSerializedExperiment(playerKevlar);
}
}
};
const controller = {
start() {
kc1 = setIntervalW(looperFn, 1);
(async () => {
while (true && !nativeFnLoaded) {
looperFn();
if (fStopLooper) break;
await (new Promise(requestAnimationFrame));
}
})();
looperFn();
},
/**
*
* @param {Window} __CONTEXT__
*/
setupForCleanContext(__CONTEXT__) {
const { requestAnimationFrame, setInterval, clearInterval, setTimeout, clearTimeout } = __CONTEXT__;
(async () => {
while (true) {
looperFn();
if (fStopLooper) break;
await (new Promise(requestAnimationFrame));
}
})();
let kc2 = setInterval(looperFn, 1);
const marcoDisconnectFn = () => {
if (fStopLooper) return;
Promise.resolve().then(() => {
if (kc1 || kc2) {
kc1 && clearIntervalW(kc1); kc1 = 0;
kc2 && clearInterval(kc2); kc2 = 0;
looperFn();
}
fStopLooper = true;
});
document.removeEventListener('yt-page-data-fetched', marcoDisconnectFn, false);
document.removeEventListener('yt-navigate-finish', marcoDisconnectFn, false);
document.removeEventListener('spfdone', marcoDisconnectFn, false);
};
document.addEventListener('yt-page-data-fetched', marcoDisconnectFn, false);
document.addEventListener('yt-navigate-finish', marcoDisconnectFn, false);
document.addEventListener('spfdone', marcoDisconnectFn, false);
function onReady() {
if (!fStopLooper) {
setTimeout(() => {
!fStopLooper && marcoDisconnectFn();
}, 1000);
}
}
Promise.resolve().then(() => {
if (document.readyState !== 'loading') {
onReady();
} else {
window.addEventListener("DOMContentLoaded", onReady, false);
}
});
nativeFnLoaded = true;
microDisconnectFn = () => Promise.resolve(marcoDisconnectFn).then(setTimeout);
}
};
return controller;
})((EXPERIMENT_FLAGS, config_) => {
if (!EXPERIMENT_FLAGS) return;
if (!settled) {
settled = {
use_maintain_stable_list: getSettingValue(ENABLE_EXPERIMENT_FLAGS_MAINTAIN_STABLE_LIST),
use_maintain_reuse_components: getSettingValue(ENABLE_EXPERIMENT_FLAGS_MAINTAIN_REUSE_COMPONENTS),
use_defer_detach: getSettingValue(ENABLE_EXPERIMENT_FLAGS_DEFER_DETACH),
}
if (settled.use_maintain_stable_list) Promise.resolve().then(() => console.debug("use_maintain_stable_list"));
if (settled.use_maintain_reuse_components) Promise.resolve().then(() => console.debug("use_maintain_reuse_components"));
if (settled.use_defer_detach) Promise.resolve().then(() => console.debug("use_defer_detach"));
}
const { use_maintain_stable_list, use_maintain_reuse_components, use_defer_detach } = settled;
cachedSet = cachedSet || cachedSetFn({ use_maintain_stable_list, use_maintain_reuse_components, use_defer_detach });
const setFalseFn = (EXPERIMENT_FLAGS) => {
for (const [key, value] of Object.entries(EXPERIMENT_FLAGS)) {
if (value === true) {
// if(key.indexOf('modern')>=0 || key.indexOf('enable')>=0 || key.indexOf('theme')>=0 || key.indexOf('skip')>=0 || key.indexOf('ui')>=0 || key.indexOf('observer')>=0 || key.indexOf('polymer')>=0 )continue;
if (mzFlagDetected.has(key)) continue;
mzFlagDetected.add(key);
// const kl = key.length;
// const kl7 = kl % 7;
// const kl5 = kl % 5;
// const kl3 = kl % 3;
// const kl2 = kl % 2;
if(cachedSet.has(key)) continue;
// console.log(key)
EXPERIMENT_FLAGS[key] = false;
}
}
}
setFalseFn(EXPERIMENT_FLAGS);
if (config_.EXPERIMENTS_FORCED_FLAGS) setFalseFn(config_.EXPERIMENTS_FORCED_FLAGS);
EXPERIMENT_FLAGS.desktop_delay_player_resizing = false;
EXPERIMENT_FLAGS.web_animated_like = false;
EXPERIMENT_FLAGS.web_animated_like_lazy_load = false;
if (use_maintain_stable_list) {
EXPERIMENT_FLAGS.kevlar_tuner_should_test_maintain_stable_list = true;
EXPERIMENT_FLAGS.kevlar_should_maintain_stable_list = true;
EXPERIMENT_FLAGS.kevlar_tuner_should_maintain_stable_list = true; // fallback
}
if (use_maintain_reuse_components) {
EXPERIMENT_FLAGS.kevlar_tuner_should_test_reuse_components = true;
EXPERIMENT_FLAGS.kevlar_tuner_should_reuse_components = true;
EXPERIMENT_FLAGS.kevlar_should_reuse_components = true; // fallback
}
if (use_defer_detach) {
EXPERIMENT_FLAGS.kevlar_tuner_should_defer_detach = true;
}
// EXPERIMENT_FLAGS.kevlar_prefetch_data_augments_network_data = true; // TBC
});
hLooper.start();
const cleanContext = async (win) => {
const waitFn = requestAnimationFrame; // shall have been binded to window
try {
let mx = 16; // MAX TRIAL
const frameId = 'vanillajs-iframe-v1'
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, setInterval, setTimeout, clearInterval, clearTimeout } = fc;
const res = { requestAnimationFrame, setInterval, setTimeout, clearInterval, clearTimeout };
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__ => {
const { requestAnimationFrame, setInterval, clearInterval, setTimeout, clearTimeout } = __CONTEXT__;
hLooper.setupForCleanContext(__CONTEXT__)
});
if (isMainWindow) {
console.groupCollapsed(
"%cYouTube EXPERIMENT_FLAGS Tamer",
"background-color: #EDE43B ; color: #000 ; font-weight: bold ; padding: 4px ;"
);
console.log("Script is loaded.");
console.log("This might affect the new features when YouTube rolls them out to general users.");
console.log("If you found any issue in using YouTube, please disable this script to check whether the issue is due to this script or not.");
console.groupEnd();
}
})(null);