expressjsHow can I use Express.js to enable CORS?

CORS (Cross-Origin Resource Sharing) is a mechanism that uses additional HTTP headers to tell a browser to let a web application running at one origin (domain) have permission to access selected resources from a server at a different origin.

Using Express.js, you can enable CORS with various options. The simplest way is to use the cors package from npm.

$ npm install cors

Then, require the package and use it with Express:

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

app.use(cors())

The cors() function can also take an options object as an argument. This object can contain various settings, such as origin, methods, allowedHeaders, credentials, etc.

app.use(cors({
  origin: 'http://example.com',
  methods: ['GET', 'POST'],
  allowedHeaders: ['Content-Type', 'Authorization']
}))

For more information, see the CORS documentation on the Express website.

You can also find more information on MDN.

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