var isCallable = require('../internals/is-callable'); var isObject = require('../internals/is-object'); var setPrototypeOf = require('../internals/object-set-prototype-of'); // makes subclassing work correct for wrapped built-ins module.exports = function ($this, dummy, Wrapper) { var NewTarget, NewTargetPrototype; if ( // it can work only with native `setPrototypeOf` setPrototypeOf && // we haven't completely correct pre-ES6 way for getting `new.target`, so use this isCallable(NewTarget = dummy.constructor) && NewTarget !== Wrapper && isObject(NewTargetPrototype = NewTarget.prototype) && NewTargetPrototype !== Wrapper.prototype ) setPrototypeOf($this, NewTargetPrototype); return $this; };