Node.js util.types.isProxy() Method

The util.types.isProxy() method is an inbuilt application programming interface of util module which is primarily designed to support the needs of Node.js own internal APIs. The util.types.isProxy() method is used to check if the given value is a proxy instance or not.

Syntax:

util.types.isProxy( value )

Parameters: This function accepts single parameter as mentioned above and described below:

• value: It is the value that would be checked for a proxy instance.

Return Value: It returns a boolean value i.e. true if the passed value is a proxy otherwise returns false.

Below programs illustrate the util.types.isProxy() method:

Example 1:

// Node.js program to demonstrate the
// util.types.isProxy() method

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

// Creating a target
const target = {};

// Checking the proxy instance
let proxyObj = new Proxy(target, {});
console.log(proxyObj);

isProxy = util.types.isProxy(proxyObj);
console.log("Object is a proxy instance:", isProxy);

// Checking a normal object
normalObj = {a: "1", b: "2"};
console.log(normalObj);

isProxy = util.types.isProxy(normalObj);
console.log("Object is a proxy instance:", isProxy);

Output:

{}
Object is a proxy instance: true
{ a: '1', b: '2' }
Object is a proxy instance: false

Example 2:

// Node.js program to demonstrate the
// util.types.isProxy() method

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

// Creating a target
const target = {};

// Checking the proxy object
console.log("Object is a proxy instance:");
console.log(util.types.isProxy(new Proxy(target, {})));

// Checking a normal object
console.log("Object is a proxy instance:");
console.log(util.types.isProxy(new Object()));

Output:

Object is a proxy instance:
true
Object is a proxy instance:
false

Reference: https://nodejs.org/api/util.html#util_util_types_isproxy_value