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