SSL settings for NODE application - express

Question

My node application port is successfully running at https://www.example.com:3001 but I have the CORS issue while submitting the details
Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at https://www.example.com:3001/user/findUser
NOTE: With out https, the application is running perfect but the SSL (https) is having an issue... Any help would be really appreciated
My code
//app.js used for configuring the application
const express = require('express'); //getting express module
const db = require('./database/database-db'); //Database connection file
const UserController = require('./user/UserController');
const DataController = require('./user/DataController');
const app = express();
const cors = require('cors');
app.use(function (req, res, next) {
// res.setHeader('Access-Control-Allow-Origin', 'http://localhost:4200');
res.setHeader('Access-Control-Allow-Origin', 'https://www.example.com');
res.setHeader('Access-Control-Allow-Methods', 'POST');
res.setHeader('Access-Control-Allow-Headers', 'X-Requested-With,content-type');
res.setHeader('Access-Control-Allow-Credentials', true);
next();
});
//importing UserController and it appears /user/allOtherURIs
app.use(cors());
app.use('/user', UserController);
app.use('/data', DataController);
app.get('/', function(req, res){
res.send('Welcome to MY-API');
});
//this should be exported because to make available all the imported modules in this file
module.exports = app;
'use strict' ;
//server.js for spinning up the node server on a specific port 3001
// var app = require('./app/app.js'); //making all the modules in app.js available
// var port = process.env.PORT || 3001 ; //setting port
// var server = app.listen(port, function(){
// console.log("Server is running on http://localhost:%s", port);
// });
//ssl port settings
var https = require('https');
var fs = require('fs');
var options = {
key: fs.readFileSync('key.key'),
cert: fs.readFileSync('cert.crt'),
};
https.createServer(options, function (req, res) {
res.writeHead(200);
res.end("Welcome");
}).listen(3001);
app.js code is:

Answer 1

Finally this is the code
var express = require('express');
var DataController = require('./user/DataController');
var UserController = require('./user/UserController');
var db = require('./database/database-db');
var cors = require('cors');
var app = express();
app.use(cors());
app.use(function(req, res, next) {
res.setHeader("Access-Control-Allow-Origin", "https://www.example.com");
res.setHeader("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
res.setHeader('Access-Control-Allow-Methods', 'POST');
res.setHeader('Access-Control-Allow-Credentials', true);
next();
});
app.use('/user', UserController);
app.use('/data', DataController);
app.get('/', function(req, res){
res.send("Welcome");
});
// This settings are for HTTPS, SSL web applications
var https = require("https");
var fs = require("fs");
var options = {
key: fs.readFileSync("key.key"),
cert: fs.readFileSync("cert.crt")
};
https.createServer(options,app).listen(3001);
console.log('Welcome')
// // This settings are only for HTTP sites
// var http = require("http");
// var fs = require("fs");
// http.createServer(app).listen(3001);
// console.log('Welcome')