☰

Automatic Material Dark-Mode for YouTube

A low-tech solution to a high-tech problem! Automatically clicks YouTube's "Dark Mode" button if dark mode isn't already active.

目前为 2017-09-21 提交的版本，查看 最新版本。

  1. // ==UserScript==
  2. // @name         Automatic Material Dark-Mode for YouTube
  3. // @namespace    SteveJobzniak
  4. // @version      1.4
  5. // @description  A low-tech solution to a high-tech problem! Automatically clicks YouTube's "Dark Mode" button if dark mode isn't already active.
  6. // @author       SteveJobzniak
  7. // @match        *://www.youtube.com/*
  8. // @exclude      *://www.youtube.com/tv*
  9. // @exclude      *://www.youtube.com/embed/*
  10. // @run-at       document-end
  11. // @grant        none
  12. // @noframes
  13. // ==/UserScript==
  14.  
  15. (function() {
  16.     'use strict';
  17.  
  18.     /* Performs multiple retries of a function call until it either succeeds or has failed all attempts. */
  19.     function retryFnCall( fnCallback ) {
  20.         // If we don't succeed immediately, we'll perform multiple retries.
  21.         var success = fnCallback();
  22.         if( ! success ) {
  23.             var attempt = 0, maxAttempts = 40, waitDelay = 50; // 40 * 50ms = Max ~2 seconds of retries.
  24.             var searchTimer = setInterval( function() {
  25.                 var success = fnCallback();
  26.  
  27.                 // If we've reached max attempts or found success, we must now stop the interval timer.
  28.                 if( ++attempt >= maxAttempts || success ) {
  29.                     clearInterval( searchTimer );
  30.                 }
  31.             }, waitDelay );
  32.         }
  33.     }
  34.  
  35.     /* Searches for a specific element. */
  36.     function findElement( parentElem, elemQuery, expectedLength, selectItem, fnCallback ) {
  37.         var elems = parentElem.querySelectorAll( elemQuery );
  38.         if( elems.length === expectedLength ) {
  39.             var item = elems[selectItem];
  40.             fnCallback( item );
  41.             return true;
  42.         }
  43.  
  44.         //console.log('Debug: Cannot find "'+elemQuery+'".');
  45.         return false;
  46.     }
  47.  
  48.     function retryFindElement( parentElem, elemQuery, expectedLength, selectItem, fnCallback ) {
  49.         // If we can't find the element immediately, we'll perform multiple retries.
  50.         retryFnCall( function() {
  51.             return findElement( parentElem, elemQuery, expectedLength, selectItem, fnCallback );
  52.         } );
  53.     }
  54.  
  55.     /* Searches for multiple different elements and uses the earliest match. */
  56.     function multiFindElement( queryList, fnCallback ) {
  57.         for( var i=0, len=queryList.length; i<len; ++i ) {
  58.             var query = queryList[i];
  59.             var success = findElement( query.parentElem, query.elemQuery, query.expectedLength, query.selectItem, fnCallback );
  60.             if( success ) {
  61.                 // Don't try any other queries, since we've found a successful match.
  62.                 return true;
  63.             }
  64.         }
  65.  
  66.         return false;
  67.     }
  68.  
  69.     function retryMultiFindElement( queryList, fnCallback ) {
  70.         // If we can't find any of the elements immediately, we'll perform multiple retries.
  71.         retryFnCall( function() {
  72.             return multiFindElement( queryList, fnCallback );
  73.         } );
  74.     }
  75.  
  76.     /* Automatically enables YouTube's dark mode theme. */
  77.     function enableDark() {
  78.         // Wait until the settings menu is available, to ensure that YouTube's "dark mode state" and code has been loaded...
  79.         // Note that this particular menu button always exists (both when logged in and when logged out of your account),
  80.         // but its actual icon and the list of submenu choices differ. However, its "dark mode" submenus are the same in either case.
  81.         retryFindElement( document, 'button.style-scope.ytd-topbar-menu-button-renderer', 2, 1, function( settingsMenuButton ) {
  82.             // Check the dark mode state "flag" and abort processing if dark mode is already active.
  83.             if( document.body.getAttribute( 'dark' ) === 'true' ) { return; }
  84.  
  85.             // We MUST open the "settings" menu, otherwise nothing will react to the "toggle dark mode" event!
  86.             settingsMenuButton.click();
  87.  
  88.             // Wait a moment for the settings-menu to open up after clicking...
  89.             retryFindElement( document, 'div#label.style-scope.ytd-toggle-theme-compact-link-renderer', 1, 0, function( darkModeSubMenuButton ) {
  90.                 // Next, go to the "toggle dark mode" settings sub-page.
  91.                 darkModeSubMenuButton.click();
  92.  
  93.                 // Wait a moment for the settings sub-page to switch...
  94.                 retryFindElement( document, 'ytd-toggle-item-renderer.style-scope.ytd-multi-page-menu-renderer', 1, 0, function( darkModeSubPageContainer ) {
  95.                     // Get a reference to the "activate dark mode" button...
  96.                     retryFindElement( darkModeSubPageContainer, 'paper-toggle-button.style-scope.ytd-toggle-item-renderer', 1, 0, function( darkModeButton ) {
  97.                         // We MUST now use this very ugly, hardcoded sleep-timer to ensure that YouTube's "activate dark mode" code is fully
  98.                         // loaded; otherwise, YouTube will be completely BUGGED OUT and WON'T save the fact that we've enabled dark mode!
  99.                         // Since JavaScript is single-threaded, this timeout simply ensures that we'll leave our current code so that we allow
  100.                         // YouTube's event handlers to deal with loading the settings-page, and then the timeout gives control back to us.
  101.                         setTimeout( function() {
  102.                             // Now simply click YouTube's button to enable their dark mode.
  103.                             darkModeButton.click();
  104.  
  105.                             // And lastly, give keyboard focus back to the input search field... (We don't need any setTimeout here...)
  106.                             retryFindElement( document, 'input#search', 1, 0, function( searchField ) {
  107.                                 searchField.click(); // First, click the search-field to force the settings-panel to close...
  108.                                 searchField.focus(); // ...and finally give the search-field focus! Voila!
  109.                             } );
  110.                         }, 20 ); // We can use 0ms here for "as soon as possible" instead, but our "at least 20ms" might be safer just in case.
  111.                     } );
  112.                 } );
  113.             } );
  114.         } );
  115.  
  116.         // Alternative method, which switches using an internal YouTube event instead of clicking
  117.         // the menus... I decided to disable this method, since it relies on intricate internal
  118.         // details, and it still requires their menu to be open to work anyway (because their
  119.         // code for changing theme isn't active until the Dark Mode settings menu is open),
  120.         // so we may as well just click the actual menu items. ;-)
  121.         /*
  122.         var ytDebugMenu = document.querySelectorAll('ytd-debug-menu');
  123.         ytDebugMenu = (ytDebugMenu.length === 1 ? ytDebugMenu[0] : undefined);
  124.         if( ytDebugMenu ) {
  125.             ytDebugMenu.fire(
  126.                 'yt-action',
  127.                 {
  128.                     actionName:'yt-signal-action-toggle-dark-theme-on',
  129.                     optionalAction:false,
  130.                     args:[
  131.                         {signalAction:{signal:'TOGGLE_DARK_THEME_ON'}},
  132.                         toggleMenuElem,
  133.                         undefined
  134.                     ],
  135.                     returnValue: []
  136.                 },
  137.                 {}
  138.             );
  139.         }
  140.         */
  141.  
  142.         // Also note that it may be possible to simply modify the YouTube cookies, by changing
  143.         // "PREF=f1=50000000;" to "PREF=f1=50000000&f6=400;" (dark mode on) and then reloading the page.
  144.         // However, a reload is always slower than toggling the settings menu, so I didn't do that.
  145.     }
  146.  
  147.     if( document.readyState === 'complete' ) {
  148.         enableDark();
  149.     } else {
  150.         document.addEventListener( 'readystatechange', function( evt ) {
  151.             if( document.readyState === 'complete' ) {
  152.                 enableDark();
  153.             }
  154.         } );
  155.     }
  156. })();