Node.js KeyObject.from() Method

The keyObject.form() method is an inbuilt application programming interface of class keyObject within the crypto module which is used to convert the CryptoKey instance in KeyObject. It is a static method of the class KeyObject.

Syntax:

keyObject.form( key ) 

Parameters: This method takes only one parameter describing below.

• key: This parameter holds the CryptoKey value.

Return Value: This method returns the instance to  KeyObject.

Example:

Filename: index.js

Javascript

// Node.js program to demonstrate the
// keyObject.form() method

// Importing the crypto module
const { webcrypto: { subtle }, KeyObject }
    = require('crypto');

// Generating the crypto key that is
// not a keyObject instance
(async function () {
    const key = await subtle.generateKey({
        name: 'HMAC',
        hash: 'SHA-256',
        length: 256
    }, true, ['sign', 'verify']);

    try {

        // Calling keyObject.form() method to
        // get the instance to keyObject
        const keyObject = KeyObject.from(key);
        console.log("Successfully converted a "
        + "cryptoKey to instance of keyObject");
    }
    catch (error) {
        console.log("Error has been occurred");
    }
})();

Run index.js file using below command:

node index.js

Output:

Successfully converted a cryptoKey to instance of keyObject.

Reference: https://nodejs.org/api/crypto.html#crypto_class_keyobject