Cors with custom headers

cors_with_headers.js

//server code

const express = require('express')
const cors = require('cors')
const app = express()
const port = 3000

//whitelist of custom headers
app.use(cors({origin: '*', exposedHeaders: 'X-LH-Auth,X-Powered-By' }))

app.get('/', (req, res) => {
  res.set({
    'Content-Type': 'text/plain',
    'Content-Length': '123',
    'X-LH-Auth': 'value'
  })
  res.json({msg: 'CORS is enabled with custom headers'});
})

app.listen(port, () => console.log(`Example app listening at http://localhost:${port}`))


//client code
fetch('http://localhost:3000', {mode: 'cors', cache: 'no-cache'}).then(response => {
  console.log(response.headers.get('Content-Type'));
  console.log(response.headers.get('X-LH-Auth'));
  console.log(response.headers.get('X-Powered-By'));
});