Example Node Server w/ Babel

Getting Started

First we'll install babel-cli.

$ npm install --save-dev babel-cli

Along with some presets.

$ npm install --save-dev babel-preset-es2015 babel-preset-stage-2

Then create our server in index.js.

$ touch index.js

import http from 'http';

http.createServer((req, res) => {
  res.writeHead(200, {'Content-Type': 'text/plain'});
  res.end('Hello World\n');
}).listen(1337, '127.0.0.1');

console.log('Server running at http://127.0.0.1:1337/');

Then we'll add our first npm start script in package.json.

  "scripts": {
+   "start": "babel-node index.js --presets es2015,stage-2"
  }

Now let's start our server.

$ npm start

You should now be able to visit http://127.0.0.1:1337 and see Hello World.

Watching file changes with nodemon

We can improve our npm start script with nodemon.

$ npm install --save-dev nodemon

Then we can update our npm start script.

  "scripts": {
-   "start": "babel-node index.js"
+   "start": "nodemon index.js --exec babel-node --presets es2015,stage-2"
  }

Then we'll restart our server.

$ npm start

You should now be able to make changes to index.js and our server should be restarted automatically by nodemon.

Go ahead and replace Hello World with Hello {{YOUR_NAME_HERE}} while our server is running.

If you visit http://127.0.0.1:1337 you should see our server greeting you.

Getting ready for production use

So we've cheated a little bit by using babel-node. While this is great for getting something going, it's not a good idea to use it in production.

We should be precompiling our files, so let's do that now.

First let's move our server index.js file to lib/index.js.

$ mv index.js lib/index.js

And update our npm start script to reflect the location change.

  "scripts": {
-   "start": "nodemon index.js --exec babel-node --presets es2015,stage-2"
+   "start": "nodemon lib/index.js --exec babel-node --presets es2015,stage-2"
  }

Next let's add two new tasks, npm run build and npm run serve.

  "scripts": {
    "start": "nodemon lib/index.js --exec babel-node --presets es2015,stage-2",
+   "build": "babel lib -d dist --presets es2015,stage-2",
+   "serve": "node dist/index.js"
  }

Now we can use npm run build for precompiling our assets, and npm run serve for starting our server in production.

$ npm run build
$ npm run serve

This means we can quickly restart our server without waiting for babel to recompile our files.

Oh, let's not forget to add dist to our .gitignore file:

$ touch .gitignore

dist

This will make sure we don't accidentally commit our built files to git.

Saving Babel options to .babelrc

Let's create a .babelrc file.

$ touch .babelrc

This will host any options we might want to configure babel with.

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

Now we can remove the duplicated options from our npm scripts

  "scripts": {
+   "start": "nodemon lib/index.js --exec babel-node",
+   "build": "babel lib -d dist",
    "serve": "node dist/index.js"
  }

Testing the server

Finally let's make sure our server is well tested.

Let's install mocha.

$ npm install --save-dev mocha

And create our test in test/index.js.

$ mkdir test
$ touch test/index.js

import http from 'http';
import assert from 'assert';

import '../lib/index.js';

describe('Example Node Server', () => {
  it('should return 200', done => {
    http.get('http://127.0.0.1:1337', res => {
      assert.equal(200, res.statusCode);
      done();
    });
  });
});

Next, install babel-register for the require hook.

$ npm install --save-dev babel-register

Then we can add an npm test script.

  "scripts": {
    "start": "nodemon lib/index.js --exec babel-node",
    "build": "babel lib -d dist",
    "serve": "node dist/index.js",
+   "test": "mocha --compilers js:babel-register"
  }

Now let's run our tests.

$ npm test

You should see the following:

Server running at http://127.0.0.1:1337/

  Example Node Server
    ✓ should return 200

  1 passing (43ms)

That's it!