Node.js – util.types.isProxy() Method

The util.types.isProxy() method checks whether the passed value is a built-in Proxy instance or not. If the above condition is satisfied, it returns True, else False.

Syntax

util.types.isProxy(value)

Parameters

It takes only one parameter −

• value − This input value takes input for the required parameter and checks if it is a Proxy instance or not.

It returns True or False based upon the input value passed.

Example 1

Create a file "isProxy.js" and copy the following code snippet. After creating the file, use the command "node isProxy.js" to run this code.

// util.types.isProxy() Demo Example

// Importing the util module
const util = require('util');

// Defining proxy and target
const target = {};
const proxy = new Proxy(target, {});

// Passing a target as input
console.log("1. " + util.types.isProxy(target));

// Passing a Proxy instance as input
console.log("2. " + util.types.isProxy(proxy));

Output

C:\home
ode>> node isFloat32Array.js
1. false
2. true

Example 2

// util.types.isProxy() Demo Example

// Importing the util module
const util = require('util');

// Defining proxy and target
const handler = {
   get: function(obj, prop) {
      return prop in obj ?
      obj[prop] :
      37;
   }
};

const p = new Proxy({}, handler);
p.a = 1;
p.b = undefined;

console.log(p.a, p.b);

console.log('c' in p, p.c);

// Passing a target as input
console.log("1." + util.types.isProxy(handler));

// Passing a Proxy instance as input
console.log("2." + util.types.isProxy(p));

Output

C:\home
ode>> node isInt8Array.js
1 undefined
false 37
1.false
2.true