section35.1.md

Section 35.1: Node ES6 Support and creating a project with Babel

• create a new node project
  • mkdir my-es6-app
    • cd my-es6-app
      • npm init

Install babel the ES6 preset and stage-0

• npm install --save-dev babel-preset-es2015 babel-preset-stage-2 babel-cli babel-register

Create a new file called server.js and add a basic HTTP server.

import http from 'http'

http.createServer((req, res) => {
  res.writeHead(200, {'Content-Type': 'text/plain'})
  res.end('Hello World\n')
}).listen(3000, '127.0.0.1');

console.log('Server running at http://127.0.0.1:3000/')

Note that we use an import http from 'http' this is a stage-0 feature and if it works it means we've got the transpiler working correctly.

If you run node server.js it will fail not knowing how to handle the import.

Creating a **.babelrc **file in the root of your directory and add the following settings

{
  "presets": ["es2015", "stage-2"],
  "plugins": []
}

you can now run the server with node src/index.js --exec babel-node

Finishing off it is not a good idea to run a transpiler at runtime on a production app. We can however implement some scripts in our package.json to make it easier to work with.

"scripts": {
  "start": "node dist/index.js",
  "dev": "babel-node src/index.js",
  "build": "babel src -d dist",
  "postinstall": "npm run build"
},

The above will on npm install build the transpiled code to the dist directory allow npm start to use the transpiled code for our production app.

npm run dev will boot the server and babel runtime which is fine and preferred when working on a project locally. Going one further you could then install nodemon npm install nodemon --save-dev to watch for changes and then reboot the node app.

This really speeds up working with babel and NodeJS. In you package.json just update the "dev" script to use nodemon

"dev": "nodemon src/index.js --exec babel-node",