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 2017-09-05 提交的版本。查看 最新版本

// ==UserScript==
// @name         Automatic Material Dark-Mode for YouTube
// @namespace    SteveJobzniak
// @version      1.0
// @description  A low-tech solution to a high-tech problem! Automatically clicks YouTube's "Dark Mode" button if dark mode isn't already active.
// @author       SteveJobzniak
// @match        *://www.youtube.com/*
// @exclude      *://www.youtube.com/tv*
// @exclude      *://www.youtube.com/embed/*
// @run-at       document-end
// @grant        none
// @noframes
// ==/UserScript==

(function() {
    'use strict';

    function enableDark() {
        // Wait a moment so that the whole page menu is loaded and the "dark mode state" is updated...
        setTimeout( function() {
            // Check the dark mode state and only process if dark mode isn't already active.
            if( document.body.getAttribute('dark') !== 'true' ) {
                // We MUST open the "settings" menu, otherwise nothing will react to the "toggle dark mode" event!
                var menuButtons = document.querySelectorAll('yt-icon.style-scope.ytd-topbar-menu-button-renderer');
                if( menuButtons.length === 2 ) {
                    menuButtons[1].click(); // Click the 2nd menu button.

                    // Wait a moment for the settings-menu to open up...
                    setTimeout( function() {
                        // Next, open the "toggle dark mode" settings sub-page.
                        var subButtons = document.querySelectorAll('div#label.style-scope.ytd-toggle-theme-compact-link-renderer');
                        if( subButtons.length === 1 ) {
                            subButtons[0].click(); // Click the "dark mode" sub-page button.

                            // Wait a moment for the sub-page to switch...
                            setTimeout( function() {
                                // Get a reference to the "toggle dark mode" settings sub-page. This only works if we opened the "dark mode" sub-page.
                                var toggleMenuElem = document.querySelectorAll('ytd-toggle-item-renderer.style-scope.ytd-multi-page-menu-renderer');
                                toggleMenuElem = (toggleMenuElem.length === 1 ? toggleMenuElem[0] : undefined); // Always missing unless we visit the page...

                                if( toggleMenuElem ) {
                                    // Get a reference to the "activate dark mode" button.
                                    var darkModeButton = toggleMenuElem.querySelectorAll('paper-toggle-button.style-scope.ytd-toggle-item-renderer');
                                    darkModeButton = (darkModeButton.length === 1 ? darkModeButton[0] : undefined);

                                    // Now simply click the button to enable dark mode.
                                    darkModeButton.click();
                                }

                                // Alternative method, which switches using an event instead of clicking the button...
                                // I decided to disable this method, since it relies on intricate internal details...
                                // and requires the menu to be open to work anyway, so we may as well just click it...
                                /*
                                var ytDebugMenu = document.querySelectorAll('ytd-debug-menu');
                                ytDebugMenu = (ytDebugMenu.length === 1 ? ytDebugMenu[0] : undefined);
                                if( ytDebugMenu ) {
                                    ytDebugMenu.fire(
                                        'yt-action',
                                        {
                                            actionName:'yt-signal-action-toggle-dark-theme-on',
                                            optionalAction:false,
                                            args:[
                                                {signalAction:{signal:'TOGGLE_DARK_THEME_ON'}},
                                                toggleMenuElem,
                                                undefined
                                            ],
                                            returnValue: []
                                        },
                                        {}
                                    );
                                }
                                */
                            }, 250 ); // Delay to wait for the dark mode settings subpage to open.
                        }
                    }, 500 ); // Delay to wait for the settings menu to fully open.
                }
            }
        }, 500 ); // Delay after page load to ensure the deferred menu topbar and dark mode state is fully loaded.
    }

    if( document.readyState === 'complete' ) {
        enableDark();
    } else {
        document.addEventListener( 'readystatechange', function( evt ) {
            if( document.readyState === 'complete' ) {
                enableDark();
            }
        } );
    }
})();