youtube-experiment-overrides.user.js

// ==UserScript==
// @name        Youtube Experiment Overrides
// @version     1.1.0
// @description Generic experiment override userscript, configurable via script storage.
// @author      voc
// @namespace   https://github.com/Vocaned
// @match       https://www.youtube.com/*
// @grant       GM_getValue
// @grant       GM_setValue
// @grant       unsafeWindow
// @run-at      document-start
// @downloadURL https://gist.github.com/Vocaned/be68a3926bef82b8c9ec01071ed3525a/raw/youtube-experiment-overrides.user.js
// @require     https://raw.githubusercontent.com/cyfung1031/userscript-supports/e0f448b8865a96e59f673d481cde2583295123ad/library/ytConfigHacks.js#sha256=fEp1NkJ5HYRTPVSDqcHXKDReJTaGTuMUOFFqXs1hJ/w=
// ==/UserScript==

// Usage:
// Violentmonkey (preferred): Edit experiments in the "values" tab of the script.
// Others: Set the overrides you want from the console using `experimentOverrides = { "web_frosted_glass": false, }`. Set to null to reset to defaults.

(() => {
  const STORAGE_KEY = 'ytExperimentOverrides';
  const DEFAULT_OVERRIDES = {
    "web_player_use_screen_width_for_big_mode": false,
    "delhi_modern_web_player": false,
    "delhi_modern_web_player_icons": false,
    "enable_web_delhi_icons": false
  };

  if (GM_getValue(STORAGE_KEY, null) === null) GM_setValue(STORAGE_KEY, DEFAULT_OVERRIDES);

  Object.defineProperty(unsafeWindow, 'experimentOverrides', {
    get: () => {
      return GM_getValue(STORAGE_KEY, null) || DEFAULT_OVERRIDES;
    },
    set: (newValue) => {
      if (typeof newValue !== "object") { console.log('[YT Overrides] Invalid input. Must be a valid JSON object or null to reset.'); return; }

      GM_setValue(STORAGE_KEY, newValue);
      if (newValue === null) console.log('[YT Overrides] Overrides reset to default. Reload the page to apply.');
      else console.log('[YT Overrides] Overrides set. Reload the page to apply.');
    },
    enumerable: true
  });

  let patchLogged = false;
  unsafeWindow._ytConfigHacks.add((config_) => {
    for (const [experimentKey, experimentValue] of Object.entries(unsafeWindow.experimentOverrides)) {
      config_.EXPERIMENT_FLAGS[experimentKey] = experimentValue;
    }

    const configs = config_.WEB_PLAYER_CONTEXT_CONFIGS || {};
    for (const [key, entry] of Object.entries(configs)) {
      if (entry && typeof entry.serializedExperimentFlags === 'string') {
        const params = new URLSearchParams(entry.serializedExperimentFlags);
        for (const [experimentKey, experimentValue] of Object.entries(unsafeWindow.experimentOverrides)) {
          params.set(experimentKey, experimentValue);
        }
        entry.serializedExperimentFlags = decodeURIComponent(params.toString().replace("+", " "));
      }
    }

    if (!patchLogged) {
      console.log('[YT Overrides] Patched experiments with overrides:', unsafeWindow.experimentOverrides);
      patchLogged = true;
    }
  });
})();