utils: cache classList.contains() calls

jakearchibald · Oct 18, 2021 · 7336aae · 7336aae
1 parent 8910bb7
commit 7336aae
Showing 1 changed file with 6 additions and 2 deletions.
diff --git a/src/js/page/utils.js b/src/js/page/utils.js
@@ -38,9 +38,13 @@ export function readFileAsText(file) {
 
 function transitionClassFunc({ removeClass = false } = {}) {
   return (element, className = 'active', transitionClass = 'transition') => {
+    const hasClass = element.classList.contains(className);
+
     if (removeClass) {
-      if (!element.classList.contains(className)) return Promise.resolve();
-    } else if (element.classList.contains(className)) return Promise.resolve();
+      if (!hasClass) return Promise.resolve();
+    } else if (hasClass) {
+      return Promise.resolve();
+    }
 
     const transitionEnd = new Promise(resolve => {
       const listener = event => {