47 lines
1.1 KiB
JavaScript
47 lines
1.1 KiB
JavaScript
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'use strict';
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var $WeakMap = typeof WeakMap === 'function' && WeakMap.prototype ? WeakMap : null;
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var $WeakSet = typeof WeakSet === 'function' && WeakSet.prototype ? WeakSet : null;
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var exported;
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if (!$WeakMap) {
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/** @type {import('.')} */
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// eslint-disable-next-line no-unused-vars
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exported = function isWeakMap(x) {
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// `WeakMap` is not present in this environment.
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return false;
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};
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}
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var $mapHas = $WeakMap ? $WeakMap.prototype.has : null;
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var $setHas = $WeakSet ? $WeakSet.prototype.has : null;
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if (!exported && !$mapHas) {
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/** @type {import('.')} */
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// eslint-disable-next-line no-unused-vars
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exported = function isWeakMap(x) {
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// `WeakMap` does not have a `has` method
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return false;
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};
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}
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/** @type {import('.')} */
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module.exports = exported || function isWeakMap(x) {
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if (!x || typeof x !== 'object') {
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return false;
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}
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try {
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$mapHas.call(x, $mapHas);
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if ($setHas) {
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try {
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$setHas.call(x, $setHas);
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} catch (e) {
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return true;
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}
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}
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// @ts-expect-error TS can't figure out that $WeakMap is always truthy here
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return x instanceof $WeakMap; // core-js workaround, pre-v3
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} catch (e) {}
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return false;
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};
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