14 lines
379 B
JavaScript
14 lines
379 B
JavaScript
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'use strict';
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var toStringTagSymbol = require('es6-symbol').toStringTag
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, toString = Object.prototype.toString
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, id = '[object WeakMap]'
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, Global = (typeof WeakMap === 'undefined') ? null : WeakMap;
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module.exports = function (x) {
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return (x && ((Global && (x instanceof Global)) ||
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(toString.call(x) === id) || (x[toStringTagSymbol] === 'WeakMap'))) ||
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false;
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};
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