14 lines
664 B
JavaScript
14 lines
664 B
JavaScript
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'use strict';
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var isObject = require('./_is-object');
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var getPrototypeOf = require('./_object-gpo');
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var HAS_INSTANCE = require('./_wks')('hasInstance');
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var FunctionProto = Function.prototype;
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// 19.2.3.6 Function.prototype[@@hasInstance](V)
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if (!(HAS_INSTANCE in FunctionProto)) require('./_object-dp').f(FunctionProto, HAS_INSTANCE, { value: function (O) {
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if (typeof this != 'function' || !isObject(O)) return false;
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if (!isObject(this.prototype)) return O instanceof this;
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// for environment w/o native `@@hasInstance` logic enough `instanceof`, but add this:
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while (O = getPrototypeOf(O)) if (this.prototype === O) return true;
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return false;
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} });
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