JavaScript - Reflect.construct() Method

Quiz

The Reflect.construct() method is used to create instances of a constructor function with a given set of arguments. It is a part of the Reflect object, which offers several static methods for manipulating objects and their properties. When you need to dynamically build an instance of a constructor function without knowing the constructor's name when coding, the Reflect.construct() method is very useful.

Syntax

Following is the syntax of JavaScript Reflect.construct() method −

Reflect.construct(target, argumentsList, newTarget)

Parameters

This method accepts three parameters. The same are described below −

target − It is a call to the target function.
argumentsList − It is a array like object specifying the arguments with which the target should be called.
newTarget − It is a optional parameter, for the constructor whose prototype to be used.

Return value

This method returns a new instance of the the target.

Examples

Example 1

Let's look at the following example, where we are going to create an instance of the class.

<html>
   <style>
      body {
         font-family: verdana;
         color: #DE3163;
      }
   </style>
   <body>
      <script>
         class x {
            constructor(a) {
               this.a = a;
            }
         }
         const instance = Reflect.construct(x, ['WELCOME']);
         document.write(instance.a);
      </script>
   </body>
</html>

If we execute the above program, it will displays a text on the webpage.

Example 2

Consider another scenario where we are going to create a instance of the class using array prototype.

<html>
   <style>
      body {
         font-family: verdana;
         color: #DE3163;
      }
   </style>
   <body>
      <script>
         class x {
            constructor(a) {
               this.a = a;
            }
         }
         const instance = Reflect.construct(x, ['TutorialsPoint'], Array);
         document.write(instance instanceof Array, " < br > "); 
               document.write(instance.a);
      </script>
   </body>
</html>

On executing the above script, it will displays a text on the webpage.

Example 3

In the following example, we are going to create a instance of the class without any arguments.

<html>
   <style>
      body {
         font-family: verdana;
         color: #DE3163;
      }
   </style>
   <body>
      <script>
         class x {
            constructor() {
               this.Company = 'Maserati';
            }
         }
         const car = Reflect.construct(x, []);
         document.write(JSON.stringify(car));
      </script>
   </body>
</html>

When we execute the above script, the output window will pop up, displaying the text on the webpage.

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