app.use((req, res, next) => {

  res.header("Access-Control-Allow-Origin", "*");

  res.header(

    "Access-Control-Allow-Headers",

    "Origin, X-Requested-With, Content-Type, Accept, Authorization"

  );

  if (req.method === "OPTIONS") {

    res.header("Access-Control-Allow-Methods", "PUT, POST, PATCH, DELETE, GET");

    return res.status(200).json({});

  }

  next();

});

const cors = require('cors');

​

const corsOption = {

    origin: ['http://localhost:3000'],

};

app.use(cors(corsOption));

//if you want in every domain then

app.use(cors())

var express = require('express')

var cors = require('cors')  //use this

var app = express()

​

app.use(cors()) //and this

​

app.get('/user/:id', function (req, res, next) {

  res.json({user: 'CORS enabled'})

})

​

app.listen(5000, function () {

  console.log('CORS-enabled web server listening on port 5000')

})

// cors install

npm install cors

​

const cors = require('cors');

app.use(cors()); // if you want to use every domain

​

const corsOption = {

    origin: ['http://localhost:3000'],

};

app.use(cors(corsOption)); // if you want to use in specific domain

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

});

// install cors

npm install cors

​

​

// install cors for all domain

var express = require('express')

var cors = require('cors')

var app = express()

​

app.use(cors())

​

app.get('/products/:id', function (req, res, next) {

  res.json({msg: 'This is CORS-enabled for all origins!'})

})

​

app.listen(80, function () {

  console.log('CORS-enabled web server listening on port 80')

})

​

​

​

​

// install cors for specific domain

var express = require('express')

var cors = require('cors')

var app = express()

​

var corsOptions = {

  origin: 'http://example.com',

  optionsSuccessStatus: 200 // some legacy browsers (IE11, various SmartTVs) choke on 204

}

​

app.get('/products/:id', cors(corsOptions), function (req, res, next) {

  res.json({msg: 'This is CORS-enabled for only example.com.'})

})

​

app.listen(80, function () {

  console.log('CORS-enabled web server listening on port 80')

})

const express = require('express');

const cors = require('cors');

​

const app = express();

​

// Enable all CORS requests

app.use(cors());

​

// ...rest of your Node.js application code

​

app.listen(3000, () => {

  console.log('Server is running on port 3000');

});

/*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}`)                                                      

  });

// Wide listing a cors to accept a specific domain route

const cors = require('cors');

​

const corsOption = {

    origin: ['http://localhost:3000'],

};

app.use(cors(corsOption));