inherit-if-required.js
693 Bytes
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 ($this, dummy, Wrapper) {
var NewTarget, NewTargetPrototype;
if (
// it can work only with native `setPrototypeOf`
setPrototypeOf &&
// we haven't completely correct pre-ES6 way for getting `new.target`, so use this
typeof (NewTarget = dummy.constructor) == 'function' &&
NewTarget !== Wrapper &&
isObject(NewTargetPrototype = NewTarget.prototype) &&
NewTargetPrototype !== Wrapper.prototype
) setPrototypeOf($this, NewTargetPrototype);
return $this;
};