Node.js Node.JS with ES6 Node ES6 Support and creating a project with Babel


Example

The whole ES6 spec is not yet implemented in its entirety so you will only be able to use some of the new features. You can see a list of the current supported ES6 features at http://node.green/

Since NodeJS v6 there has been pretty good support. So if you using NodeJS v6 or above you can enjoy using ES6. However, you may also want to use some of the unreleased features and some from beyond. For this you will need to use a transpiler

It is possible to run a transpiler at run time and build, to use all of the ES6 features and more. The most popular transpiler for JavaScript is called Babel

Babel allows you to use all of the features from the ES6 specification and some additional not-in-spec features with 'stage-0' such as import thing from 'thing instead of var thing = require('thing')

If we wanted to create a project where we use 'stage-0' features such as import we would need to add Babel as a transpiler. You'll see projects using react and Vue and other commonJS based patterns implement stage-0 quite often.

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",