fix DOMTokenList.prototype.{ forEach, @@iterator, keys, values, entries } in old WebKit versions where element.classList is not an instance of global DOMTokenList

https://github.com/Financial-Times/polyfill-library/pull/1097

Author: zloirock

CHANGELOG.md

@@ -1,6 +1,7 @@
 ## Changelog
 ##### Unreleased
 - Fixed some possible problems related to possible extension of `%IteratorPrototype%` and `%AsyncIteratorPrototype%` in the future
+- Fixed `DOMTokenList.prototype.{ forEach, @@iterator, keys, values, entries }` in old WebKit versions where `element.classList` is not an instance of global `DOMTokenList`
 - Added NodeJS 16.9 compat data mapping
 - Added Samsung Internet 16.0 compat data mapping
 

packages/core-js/internals/dom-token-list-prototype.js

@@ -0,0 +1,7 @@
+// in old WebKit versions, `element.classList` is not an instance of global `DOMTokenList`
+var documentCreateElement = require('../internals/document-create-element');
+
+var classList = documentCreateElement('span').classList;
+var DOMTokenListPrototype = classList && classList.constructor && classList.constructor.prototype;
+
+module.exports = DOMTokenListPrototype === Object.prototype ? undefined : DOMTokenListPrototype;

packages/core-js/modules/web.dom-collections.for-each.js

@@ -1,15 +1,20 @@
 var global = require('../internals/global');
 var DOMIterables = require('../internals/dom-iterables');
+var DOMTokenListPrototype = require('../internals/dom-token-list-prototype');
 var forEach = require('../internals/array-for-each');
 var createNonEnumerableProperty = require('../internals/create-non-enumerable-property');
 
-for (var COLLECTION_NAME in DOMIterables) {
-  var Collection = global[COLLECTION_NAME];
-  var CollectionPrototype = Collection && Collection.prototype;
+var handlePrototype = function (CollectionPrototype) {
   // some Chrome versions have non-configurable methods on DOMTokenList
   if (CollectionPrototype && CollectionPrototype.forEach !== forEach) try {
     createNonEnumerableProperty(CollectionPrototype, 'forEach', forEach);
   } catch (error) {
     CollectionPrototype.forEach = forEach;
   }
+};
+
+for (var COLLECTION_NAME in DOMIterables) {
+  handlePrototype(global[COLLECTION_NAME] && global[COLLECTION_NAME].prototype);
 }
+
+handlePrototype(DOMTokenListPrototype);

packages/core-js/modules/web.dom-collections.iterator.js

@@ -1,5 +1,6 @@
 var global = require('../internals/global');
 var DOMIterables = require('../internals/dom-iterables');
+var DOMTokenListPrototype = require('../internals/dom-token-list-prototype');
 var ArrayIteratorMethods = require('../modules/es.array.iterator');
 var createNonEnumerableProperty = require('../internals/create-non-enumerable-property');
 var wellKnownSymbol = require('../internals/well-known-symbol');
@@ -8,9 +9,7 @@ var ITERATOR = wellKnownSymbol('iterator');
 var TO_STRING_TAG = wellKnownSymbol('toStringTag');
 var ArrayValues = ArrayIteratorMethods.values;
 
-for (var COLLECTION_NAME in DOMIterables) {
-  var Collection = global[COLLECTION_NAME];
-  var CollectionPrototype = Collection && Collection.prototype;
+var handlePrototype = function (CollectionPrototype, COLLECTION_NAME) {
   if (CollectionPrototype) {
     // some Chrome versions have non-configurable methods on DOMTokenList
     if (CollectionPrototype[ITERATOR] !== ArrayValues) try {
@@ -30,4 +29,10 @@ for (var COLLECTION_NAME in DOMIterables) {
       }
     }
   }
+};
+
+for (var COLLECTION_NAME in DOMIterables) {
+  handlePrototype(global[COLLECTION_NAME] && global[COLLECTION_NAME].prototype, COLLECTION_NAME);
 }
+
+handlePrototype(DOMTokenListPrototype, 'DOMTokenList');