access the .next method once, at the beginning, of the iteration pr…

…otocol, missed cases tc39/ecma262#976 tc39/ecma262#988 tc39/ecma262#1021
zloirock · Sep 1, 2019 · 2dff41a · 2dff41a
1 parent a241c18
commit 2dff41a
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Showing 4 changed files with 14 additions and 9 deletions.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -3,6 +3,7 @@
 - Added a workaround for iOS Safari MessageChannel + bfcache bug, [#624](https:/zloirock/core-js/issues/624) 
 - Added compat data for Node 12.9, FF 69 and Phantom 1.9
 - Fixed unnecessary exposing on `Symbol.matchAll` in `esnext.string.match-all`, [#626](https:/zloirock/core-js/issues/626)
+- Fixed missed cases [access the `.next` method once, at the beginning, of the iteration protocol](https:/tc39/ecma262/issues/976)
 - Show similar `postinstall` messages only once per `npm i`, [#597](https:/zloirock/core-js/issues/597), thanks [@remy](https:/remy)
 
 ##### 3.2.1 - 2019.08.12

diff --git a/packages/core-js/internals/array-from.js b/packages/core-js/internals/array-from.js
@@ -17,13 +17,14 @@ module.exports = function from(arrayLike /* , mapfn = undefined, thisArg = undef
  var mapping = mapfn !== undefined;
  var index = 0;
  var iteratorMethod = getIteratorMethod(O);
- var length, result, step, iterator;
+ var length, result, step, iterator, next;
  if (mapping) mapfn = bind(mapfn, argumentsLength > 2 ? arguments[2] : undefined, 2);
  // if the target is not iterable or it's an array with the default iterator - use a simple case
  if (iteratorMethod != undefined && !(C == Array && isArrayIteratorMethod(iteratorMethod))) {
  iterator = iteratorMethod.call(O);
+ next = iterator.next;
  result = new C();
- for (;!(step = iterator.next()).done; index++) {
+ for (;!(step = next.call(iterator)).done; index++) {
  createProperty(result, index, mapping
  ? callWithSafeIterationClosing(iterator, mapfn, [step.value, index], true)
  : step.value

diff --git a/packages/core-js/internals/typed-array-from.js b/packages/core-js/internals/typed-array-from.js
@@ -11,11 +11,12 @@ module.exports = function from(source /* , mapfn, thisArg */) {
  var mapfn = argumentsLength > 1 ? arguments[1] : undefined;
  var mapping = mapfn !== undefined;
  var iteratorMethod = getIteratorMethod(O);
- var i, length, result, step, iterator;
+ var i, length, result, step, iterator, next;
  if (iteratorMethod != undefined && !isArrayIteratorMethod(iteratorMethod)) {
  iterator = iteratorMethod.call(O);
+ next = iterator.next;
  O = [];
- while (!(step = iterator.next()).done) {
+ while (!(step = next.call(iterator)).done) {
  O.push(step.value);
  }
  }

diff --git a/packages/core-js/modules/web.url-search-params.js b/packages/core-js/modules/web.url-search-params.js
@@ -121,7 +121,7 @@ var URLSearchParamsConstructor = function URLSearchParams(/* init */) {
  var init = arguments.length > 0 ? arguments[0] : undefined;
  var that = this;
  var entries = [];
- var iteratorMethod, iterator, step, entryIterator, first, second, key;
+ var iteratorMethod, iterator, next, step, entryIterator, entryNext, first, second, key;
 
  setInternalState(that, {
  type: URL_SEARCH_PARAMS,
@@ -135,12 +135,14 @@ var URLSearchParamsConstructor = function URLSearchParams(/* init */) {
  iteratorMethod = getIteratorMethod(init);
  if (typeof iteratorMethod === 'function') {
  iterator = iteratorMethod.call(init);
- while (!(step = iterator.next()).done) {
+ next = iterator.next;
+ while (!(step = next.call(iterator)).done) {
  entryIterator = getIterator(anObject(step.value));
+ entryNext = entryIterator.next;
  if (
- (first = entryIterator.next()).done ||
- (second = entryIterator.next()).done ||
- !entryIterator.next().done
+ (first = entryNext.call(entryIterator)).done ||
+ (second = entryNext.call(entryIterator)).done ||
+ !entryNext.call(entryIterator).done
  ) throw TypeError('Expected sequence with length 2');
  entries.push({ key: first.value + '', value: second.value + '' });
  }