JavaScript handler.construct() Method

Last Updated : 17 Mar 2025

The handler.construct() method is used to intercept the new operation. This method returns an object.

Syntax

Parameters

Target: The target object.

argumentsList: List of the constructor.

newTarget: The constructor that was originally called, p above.

Return value

This method returns an object.

Browser Support

Chrome	49
Edge	12
Firefox	18
Opera	36

Example 1

var B= function(text) {
  this.text = text;
};
var Button1 = new Proxy(B, {
  construct: function(target, parameters) {
document.writeln('Java Script');

    var button= Object.create(target.prototype);
    target.apply(button, parameters);
    return button;
  }
});

var button = new Button1('proxy Constructor');
document.writeln(button.text);

Output:

Java Script proxy Constructor

Example 2

var pro = new Proxy(function()
                    {}, {
  construct: function(objTarget, args, oldConstructor) {
     return { Value : args[0] + " to anybody" }	
  }
})

document.write(JSON.stringify(new pro("Hello "), null, ' '))

Output:

{ "Value": "Hello to anybody" }

Example 3

function M(val) {
  this.val = val;
}

const N = {
  construct(target, args) {
  document.writeln('Constructor called');
  return new target(...args);
  }
};
const proxy= new Proxy(M, N)
document.writeln(new proxy('Proxi').val);

Output:

Constructor called Proxi

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JavaScript handler.construct() Method

Syntax

Parameters

Return value

Browser Support

Example 1

Example 2

Example 3

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