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A JavaScript engine optimized for running React Native.

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Add polyfill for the Iterator object Summary: Adapted from the iterator helper polyfill in https://github.com/es-shims/iterator-helpers This adds the polyfill for the global `Iterator` object and its constructor. `Iterator.prototype` methods will be added in future changes. Note that the original polyfill had many dependencies. The dependencies are taken and flattened in `05-IteratorHelperDependencies.js`. Some dependencies are purposely taken out since Hermes already supports it and does not require a polyfill for it. The actual Iterator object is added in `06-IteratorObject.js` Reviewed By: avp Differential Revision: D84199898 fbshipit-source-id: 7e6ed0fc578cb6e368f240a28cafbcfc2bc33613
2025-11-19 20:37:17 -08:00
/* @nolint */
/**
* MIT License
* Portions Copyright (c) Meta Platforms, Inc. and affiliates.
* Copyright (c) 2022 ECMAScript Shims
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
var arrayIterProto = GetIntrinsic('%ArrayIteratorPrototype%', true);
var iterProto = arrayIterProto && getProto(arrayIterProto);
var result = (iterProto !== Object.prototype && iterProto) || {};
// Check for symbol support and add Symbol.iterator if needed
if (typeof Symbol !== 'undefined' && Symbol.iterator) {
if (!(Symbol.iterator in result)) {
// needed when result === iterProto, or, node 0.11.15 - 3
var iter = setFunctionName(function SymbolIterator() {
return this;
}, '[Symbol.iterator]', true);
defineDataProperty(result, Symbol.iterator, iter, true);
}
}
var iteratorPrototype = result;
// === Main Iterator Constructor ===
// From Iterator/implementation.js
var $defineProperty = hasPropertyDescriptors() && GetIntrinsic('%Object.defineProperty%', true);
var $isPrototypeOf = callBound('Object.prototype.isPrototypeOf');
var $Iterator = typeof Iterator === 'function' ? Iterator : function Iterator() {
if (
!(this instanceof Iterator)
|| this.constructor === Iterator
|| !$isPrototypeOf(Iterator, this.constructor)
) {
throw new TypeError('`Iterator` can not be called or constructed directly');
}
};
defineProperties(
iteratorPrototype,
{ constructor: $Iterator },
{ constructor: function () { return $Iterator.constructor !== $Iterator; } }
);
Fix polyfill for `Iterator.prototype` Summary: The original polyfill for `Iterator.prototype.constructor` did not have the correct behavior for the getter and setter, so fix it. Same for `Iterator.prototype [ %Symbol.toStringTag% ]` This uses the polyfill for the abstract operation [SetterThatIgnoresPrototypeProperties](https://github.com/es-shims/es-abstract/blob/ba4a616318c6a9854d17f771dcae718d90b8939e/2025/SetterThatIgnoresPrototypeProperties.js) to implement the correct behavior. Reviewed By: avp Differential Revision: D84216767 fbshipit-source-id: e69fb93116d238109ec713c8fd81f311890cbf7d
2025-11-19 20:37:17 -08:00
Object.defineProperty(iteratorPrototype, 'constructor', {
configurable: true,
enumerable: false,
get: function () {
return $Iterator;
},
set: function (v) {
SetterThatIgnoresPrototypeProperties(this, iteratorPrototype, 'constructor', v);
return undefined;
}
});
Object.defineProperty(iteratorPrototype, Symbol.toStringTag, {
configurable: true,
enumerable: false,
get: function () {
return 'Iterator';
},
set: function (v) {
SetterThatIgnoresPrototypeProperties(this, iteratorPrototype, Symbol.toStringTag, v);
return undefined;
}
});
Add polyfill for the Iterator object Summary: Adapted from the iterator helper polyfill in https://github.com/es-shims/iterator-helpers This adds the polyfill for the global `Iterator` object and its constructor. `Iterator.prototype` methods will be added in future changes. Note that the original polyfill had many dependencies. The dependencies are taken and flattened in `05-IteratorHelperDependencies.js`. Some dependencies are purposely taken out since Hermes already supports it and does not require a polyfill for it. The actual Iterator object is added in `06-IteratorObject.js` Reviewed By: avp Differential Revision: D84199898 fbshipit-source-id: 7e6ed0fc578cb6e368f240a28cafbcfc2bc33613
2025-11-19 20:37:17 -08:00
$Iterator.prototype = iteratorPrototype;
$defineProperty($Iterator, 'prototype', { writable: false });
defineProperties(
globalThis,
{ Iterator: $Iterator },
{ Iterator: function () { return Iterator !== $Iterator; } }
);
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