diff --git a/resources/skins.vector.js/echo.js b/resources/skins.vector.js/echo.js
index 8fc973582..f125d0e76 100644
--- a/resources/skins.vector.js/echo.js
+++ b/resources/skins.vector.js/echo.js
@@ -11,16 +11,16 @@ function init() {
 		const element = badge.$element[ 0 ];
 		element.classList.add( 'mw-list-item' );
 
-		const iconButtonClasses = 'mw-ui-button mw-ui-quiet mw-ui-icon mw-ui-icon-element ';
+		const iconButtonClasses = [ 'mw-ui-button', 'mw-ui-quiet', 'mw-ui-icon', 'mw-ui-icon-element' ];
 		if ( element.id === 'pt-notifications-alert' ) {
 			const anchor = element.querySelector( 'a' );
-			anchor.classList.add( iconButtonClasses + 'mw-ui-icon-bell' );
+			anchor.classList.add( ...iconButtonClasses, 'mw-ui-icon-bell' );
 			anchor.classList.remove( 'oo-ui-icon-bell' );
 		}
 		if ( element.id === 'pt-notifications-notice' ) {
 
 			const anchor = element.querySelector( 'a' );
-			anchor.classList.add( iconButtonClasses + 'mw-ui-icon-tray' );
+			anchor.classList.add( ...iconButtonClasses, 'mw-ui-icon-tray' );
 			anchor.classList.remove( 'oo-ui-icon-tray' );
 		}
 	} );