MediaWiki:Gadget-toggleDarkMode.js

 ;(function($, mw) {
	 var DARKMODE_COOKIE = "darkmode",
	 	 currentDark = localStorage.getItem(DARKMODE_COOKIE),
		 portletLink;

	 let self = {
		 init: function() {
			portletLink = mw.util.addPortletLink(
				'p-personal',
				'',
				'',
				'pt-skin-toggles',
				'Toggle darkmode',
				null,
				$('#pt-userpage, #pt-anonuserpage')
			);
			$(portletLink).find('a').addClass('oo-ui-icon-advanced').add('.floor-convention').click(function(e) {
				e.preventDefault();
				if (!formMade) {
					mw.loader.using(['oojs-ui-core','oojs-ui-windows','oojs-ui-widgets']).then(self.initForm);
				} else {
					window.OOUIWindowManager.openWindow('skin');
				}
		 	})
		}
	}

	$(self.init);

	

 }(jQuery, mediaWiki));