JWT assertion Node JS

jwt-user-asseration.js

var jwt = require('jsonwebtoken');
const fs = require('fs');
var request = require("request");
var querystring = require('querystring');
var privateKey = fs.readFileSync('./private_key.pem');

#idcs or keycloak URL
var url = "https://example.com/oauth2/v1/token"
var headers = {
    'Authorization': 'Basic <BASE-64 ENCODED client ID & Secret>',
    'Content-Type': 'application/x-www-form-urlencoded;charset=UTF-8'
};

var token = jwt.sign({
"sub": "ADMIN",
"jti": "8c7df446-bfae-40be-be09-0ab55c655436",
"iat": 1589889699,
"exp": 1691579765,
"iss": "<Issue or client ID>",
"aud": "https://identity.oraclecloud.com/"
}, privateKey, { algorithm: 'RS256', header: {
"alg": "RS256",
"typ": "JWT",
"kid": "assert"
} });

var data = querystring.stringify({
    grant_type : 'urn:ietf:params:oauth:grant-type:jwt-bearer',
    assertion : token,
    scope: 'rest-api'
});

request.post({headers: headers, url: url, body: data, method: 'POST'}, function(error, response, body) {
   if (!error && response.statusCode == 200) {
     console.log("Sucess", response.statusCode);
     console.log("Body", response.body);
   }else{
   	console.log("Failed", response.statusCode);
   	console.log("Error", error)
   }
 });