MediaWiki:Gadget-darkmode.js

;(function($, mw){
	var DARK_COOKIE = 'darkmode',
		THEME_COOKIE = 'theme',
		isUsingDarkmode = $.cookie(THEME_COOKIE) === 'dark' || ($.cookie(THEME_COOKIE) == null && $.cookie(DARK_COOKIE) === 'true'),
		portletLink;

	var self = {
		init: function () {
			$.cookie(THEME_COOKIE, isUsingDarkmode ? 'dark' : 'light', {expires: 365, path: '/'});

			portletLink = mw.util.addPortletLink(
				'p-personal',
				'',
				'',
				'pt-dm-toggle',
				'Toggle dark mode',
				null,
				$('#pt-userpage, #pt-anonuserpage, #pt-createaccount')[0]
			);
			
			$(portletLink).find('a').click(function(e) {
				e.preventDefault();
				
				isUsingDarkmode = !isUsingDarkmode;
				$.cookie(THEME_COOKIE, isUsingDarkmode ? 'dark' : 'light', {expires: 365, path: '/'});
				$.cookie(DARK_COOKIE, isUsingDarkmode, {expires: 365, path: '/'});
				
				if (isUsingDarkmode === true) {
					mw.loader.using(['wgl.theme.dark']).then(function() {
					  $('body').addClass('wgl-theme-dark')
					  $('body').removeClass('wgl-theme-light')
					});
				} else {
					$('body').addClass('wgl-theme-light')
					$('body').removeClass('wgl-theme-dark')
				}
			});
		}
	}
	
	$(self.init);

}(jQuery, mediaWiki));