JAVASCRIPT

nodejs CORS policy

app.use(function(req, res, next) {
  res.header("Access-Control-Allow-Origin", "YOUR-DOMAIN.TLD"); // update to match the domain you will make the request from
  res.header("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
  next();
});

app.get('/', function(req, res, next) {
  // Handle the get for this route
});

app.post('/', function(req, res, next) {
 // Handle the post for this route
});

cors in node js

// Wide listing a cors to accept a specific domain route
const cors = require('cors');

const corsOption = {
    origin: ['http://localhost:3000'],
};
app.use(cors(corsOption));

add express and cors to nodejs app

/*index.js*/                                                         
const express = require( 'express' );                                                             
const cors = require( 'cors' );
const app = express();                                                                                          const port = 3030;
//cors is enabled through out the entire app                                                                                  
app.use( cors() );
app.get( '/users', (request, response, next) => {                                                                                                                                                                                                                                                                            res.json( { info: 'cors is enabled' } )                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        });
app.listen( port, () => {                                                              
  console.log(`App is running on ${port}`)                                                      
  });

cors problem node js

//install package =>   npm i cors
const cors = require('cors');
const app = express()
app.use(cors()); // use this cors in middleware and done

express cors policy

$ npm install cors