JavaScript Reflect construct() Method

by Online Tutorials Library July 22, 2022

JavaScript Reflect.construct() Method

The static Reflect.construct() method allows to invoke a constructor with a variable number of arguments. It gives also the added option to specify a different prototype.

Syntax

Parameter

target: It is the target function to call.

argumentsList: It is an array-like object specifying the arguments with which target should be called.

newTarget: It is a constructor whose prototype should be used. See also the new.target operator. If newTarget is not present, it will treat as a target.

Return

This method returns a new instance of the target (or newTarget if present), initialized by the target as a constructor with the given arguments.

Exceptions

This exception will throw a TypeError if target or newTarget are not constructors.

Example 1

  const a = new Array(1,2,3);  const b = Reflect.construct ( Array, [1,2,3] );  console.log(a);  console.log(b);  

Output:

 [1, 2, 3]   [1, 2, 3]

Example 2

  function func1(a, b, c) {    this.sum = a + b + c;  }  const args = [1, 2, 3];  const object1 = new func1(…args);  console.log(object1.sum);  

Output:

Example 3

  function func1(a, b, c) {    this.sum = a + b + c;  }  function func2(a, b, c) {    this.sum = a + b + c;  }  const args2 = [1, 4, 3];  const args = [1, 2, 3];  const object1 = new func1(…args);  const object2 = Reflect.construct(func2, args2);  console.log(object2.sum);  console.log(object1.sum);  

Output:

8   6

Next TopicJavaScript Reflect

apply() construct()defineProperty() method deleteProperty()get getOwnPropertyDescriptor()getPrototypeOf()has()isExtensible()javascript reflect methods ownKeys()setPrototypeOf()

JavaScript Reflect construct() Method

JavaScript Reflect.construct() Method

Syntax

Parameter

Return

Exceptions

Example 1

Example 2

Example 3

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