The static Reflect.construct() method acts like the new operator as a function. It is equivalent to calling new target(...args).


Reflect.construct(target, argumentsList[, newTarget])


The target function to call.
An array-like object specifying the arguments with which target should be called.
newTarget Optional
The constructor to be used. See also the operator. If newTarget is not present, it is target.

Return value

A new instance of the given target, created by calling it (or newTarget, if present) as a constructor with the given arguments.


A TypeError, if target or newTarget are not constructors.


Reflect.construct allows you to invoke a constructor with a variable number of arguments (which would also be possible by using the spread operator combined with the new operator).

var obj = new Foo(...args);
var obj = Reflect.construct(Foo, args);


Using Reflect.construct()

var d = Reflect.construct(Date, [1776, 6, 4]);
d instanceof Date; // true
d.getFullYear(); // 1776

Using the newTarget parameter

See also classes for more information about sub-classing and the operator.

function someConstructor() {}
var result = Reflect.construct(Array, [], someConstructor);

Reflect.getPrototypeOf(result); // someConstructor.prototype
Array.isArray(result); // true


Specification Status Comment
ECMAScript 2015 (6th Edition, ECMA-262)
The definition of 'Reflect.construct' in that specification.
Standard Initial definition.
ECMAScript 2017 Draft (ECMA-262)
The definition of 'Reflect.construct' in that specification.

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support 49 42 (42) No support No support No support
Feature Android Chrome for Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support No support No support 42.0 (42) No support No support No support

See also


© 2016 Mozilla Contributors
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.