sanguozhanji/packages/hot-update-tools/node_modules/core-js/modules/es6.reflect.construct.js

// 26.1.2 Reflect.construct(target, argumentsList [, newTarget])
var $export   = require('./_export')
  , create    = require('./_object-create')
  , aFunction = require('./_a-function')
  , anObject  = require('./_an-object')
  , isObject  = require('./_is-object')
  , bind      = require('./_bind');

// MS Edge supports only 2 arguments
// FF Nightly sets third argument as `new.target`, but does not create `this` from it
$export($export.S + $export.F * require('./_fails')(function(){
  function F(){}
  return !(Reflect.construct(function(){}, [], F) instanceof F);
}), 'Reflect', {
  construct: function construct(Target, args /*, newTarget*/){
    aFunction(Target);
    var newTarget = arguments.length < 3 ? Target : aFunction(arguments[2]);
    if(Target == newTarget){
      // w/o altered newTarget, optimization for 0-4 arguments
      if(args != undefined)switch(anObject(args).length){
        case 0: return new Target;
        case 1: return new Target(args[0]);
        case 2: return new Target(args[0], args[1]);
        case 3: return new Target(args[0], args[1], args[2]);
        case 4: return new Target(args[0], args[1], args[2], args[3]);
      }
      // w/o altered newTarget, lot of arguments case
      var $args = [null];
      $args.push.apply($args, args);
      return new (bind.apply(Target, $args));
    }
    // with altered newTarget, not support built-in constructors
    var proto    = newTarget.prototype
      , instance = create(isObject(proto) ? proto : Object.prototype)
      , result   = Function.apply.call(Target, instance, args);
    return isObject(result) ? result : instance;
  }
});