From 4cde844ffe6e2e129fab778a24ad5273dabcb59c Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Fri, 12 Oct 2018 15:25:38 +0200
Subject: [PATCH] Add a `DOMTokenList.toggle` polyfill for the second,
 optional, "force" parameter

This is based on the polyfill available at https://developer.mozilla.org/en-US/docs/Web/API/Element/classList#Polyfill
---
 src/shared/compatibility.js | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/src/shared/compatibility.js b/src/shared/compatibility.js
index d1417421b..66eff0591 100644
--- a/src/shared/compatibility.js
+++ b/src/shared/compatibility.js
@@ -90,6 +90,28 @@ const hasDOM = typeof window === 'object' && typeof document === 'object';
   };
 })();
 
+// Provides support for DOMTokenList.prototype.toggle, with the optional
+// "force" parameter, in legacy browsers.
+// Support: IE
+(function checkDOMTokenListToggle() {
+  if (!hasDOM || isNodeJS()) {
+    return;
+  }
+  const div = document.createElement('div');
+  if (div.classList.toggle('test', 0) === false) {
+    return;
+  }
+  const originalDOMTokenListToggle = DOMTokenList.prototype.toggle;
+
+  DOMTokenList.prototype.toggle = function(token) {
+    if (arguments.length > 1) {
+      const force = !!arguments[1];
+      return (this[force ? 'add' : 'remove'](token), force);
+    }
+    return originalDOMTokenListToggle(token);
+  };
+})();
+
 // Provides support for String.prototype.includes in legacy browsers.
 // Support: IE, Chrome<41
 (function checkStringIncludes() {