core-js/internals/inherit-if-required.js

Standard library

'use strict';
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;
};