28 lines
909 B
Plaintext
28 lines
909 B
Plaintext
"use strict";
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var isPrototype = require("../prototype/is");
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// In theory we could rely on Symbol.toStringTag directly,
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// still early native implementation (e.g. in FF) predated symbols
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var objectToString = Object.prototype.toString, objectTaggedString = objectToString.call(new Set());
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module.exports = function (value) {
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if (!value) return false;
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// Sanity check (reject objects which do not expose common Set interface)
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try {
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if (typeof value.add !== "function") return false;
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if (typeof value.has !== "function") return false;
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if (typeof value.clear !== "function") return false;
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} catch (error) {
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return false;
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}
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// Ensure its native Set object (has [[SetData]] slot)
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// Note: it's not 100% precise as string tag may be overriden
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// and other objects could be hacked to expose it
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if (objectToString.call(value) !== objectTaggedString) return false;
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return !isPrototype(value);
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};
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