Node.js diffieHellman.setPrivateKey() Method

// Node.js program to demonstrate the
// diffieHellman.setPrivateKey() Method

const crypto = require('crypto')

// Generate DH Key pair
crypto.generateKeyPair('dh', 
    {
        primeLength: 512,
         publicKeyEncoding: {
            type: 'spki',
            format: 'der'
        },
        privateKeyEncoding: {
            type: 'pkcs8',
            format: 'der'
        }
    },
    cb
)

function cb(err, publicKey, privateKey){
    // Create Diffie-Hellman instance
    const dh = crypto.createDiffieHellman(512)
    // Set the dh's privateKey
    dh.setPrivateKey(privateKey)

    if( privateKey.equals(dh.getPrivateKey()) )
        console.log("DH private Key is set successfully")
}

// Node.js program to demonstrate the
// diffieHellman.setPrivateKey() Method

const crypto = require( 'crypto' )

crypto.generateKeyPair( 
    'dh', 
    { primeLength: 512 }, 
    cb 
)

function cb( err, publicKey, privateKey ){
    // Export key from KeyObject
    privateKey = privateKey.export( {type: 'pkcs8', format: 'der'} )
    // Encode key in base64
    privateKey = privateKey.toString('base64');
    // Create Diffie-Hellman instance
    const dh = crypto.createDiffieHellman( 512 )
    // Set the dh's privateKey
    dh.setPrivateKey( privateKey, 'base64' )

    if( privateKey === dh.getPrivateKey('base64')  )
        console.log( "DH private Key is set successfully" )
}