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

Parameters

target

The target function to call.

argumentsList

An array-like object specifying the arguments with which target should be called.

Vols College Orange 1 Jersey Jason Stitched Limited newTarget Optional

The constructor whose prototype should be used. See also the  operator. If newTarget is not present, it is target.

Return value

A new instance of target (or newTargetRed 2014 Jersey Patch College Orange Buckeyes Bowl 33 Stitched Discover, if present), initialized by target as a constructor with the given arguments.

Exceptions

A , 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 combined with the ).

var obj = new FooVols College Orange 1 Jersey Jason Stitched Limited (...args);
var obj = Reflect.construct(Foo, args);

Reflect.construct() vs Object.create()

Prior to the introduction of Reflect, objects could be constructed using an arbitrary combination of constructor and prototype by using .

function OneClassVols College Orange 1 Jersey Jason Stitched Limited () {
    this.name = 'one'Vols College Orange 1 Jersey Jason Stitched Limited ;
}

function OtherClass() {
    this.name = 'other';
}

// Calling this:
var obj1 = Reflect.construct(OneClass, args, OtherClass);

// ...has the same result as this:
var obj2 = ObjectVols College Orange 1 Jersey Jason Stitched Limited .create(OtherClass.prototype);
OneClass.apply(obj2, args);

console.log(obj1.name); // 'one'
consoleVols College Orange 1 Jersey Jason Stitched Limited .log(obj2.name); // 'one'

console.log(obj1 instanceof OneClass); // false
console.log(obj2 instanceof OneClass); // false

console.log(obj1 instanceof OtherClass); // true
console.log(obj2 instanceof OtherClass)Mike College New 2 Bercovici Devils Sun Stitched Jersey Grey; // trueVols College Orange 1 Jersey Jason Stitched Limited 2014 Jersey College Orange Buckeyes Holmes Stitched Santonio Discover 4 Red Bowl PatchVols College Orange 1 Jersey Jason Stitched Limited 

However, while the end result is the same, there is one important difference in the process. When using Object.create() and , the new.target operator will point to undefined within the function used as the constructor, since the new keyword is not being used to create the object.

When invoking Reflect.construct(), on the other hand, the new.target operator will point to the newTarget parameter if supplied, or target if not.

function Vols College Orange 1 Jersey Jason Stitched Limited OneClass() {
    console.logJersey Royal Blue Calipari College Basketball Elite John Wildcats 1 Stitched('OneClass');
    console.log(new.target);
}
function OtherClass() {
    console.log('OtherClass');
    console.log(new.target);
}

var obj1 = Reflect.construct(OneClass, args);
// Output:
// OneClass
// function OneClass { ... }

var obj2 = Reflect.construct(OneClass, args, OtherClass);
// Output:
// OneClass
// function OtherClass { ... }

var obj3 = Object.create(OtherClass.prototypeVols College Orange 1 Jersey Jason Stitched Limited );
OneClass.apply(obj3, args);
// Output:
// OneClass
// undefined

Using Reflect.construct()

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