Node.js

A survival guide.

Why?

I/O takes time.

Threads spend most of their time waiting.

What?

Node.js

JavaScript + libuv + V8

JavaScript

const exec = require('child_process').exec;
const argv = process.argv.slice(2);
const dir = argv[0];

if (!dir) throw new ReferenceError('Missing arg: dir');

exec(`git -C ${dir} log`, (err, log) => {
  if (err) throw err;
  console.log(log);
});

Good ol' js.

V8

JavaScript to native code compiler.

C++ JavaScript engine.

libuv

C library to manage asynchronous I/O.

Allows nodejs to play with I/O events (file systems, TCP/UDP, etc.).

JavaScript

Callbacks

Non-blocking I/O

NPM

Callbacks

console.log('Hello!');
require('fs').readFile('./data.json', (err, data) => {
    if (err) throw err;
    console.log('Wait... Am I?');
    console.dir(JSON.parse(data), {depth: null});
});
console.log('I am a unicorn!');

// output:
// Hello!
// I'm a unicorn!
// Wait... Am I still?
// "./data.json" content

Non-blocking I/O

CPU-heavy tasks :(

NPM

{
  "name": "day-1",
  "version": "0.0.0",
  "description": "An API server in Hapi.js",
  "main": "server.js",
  "directories": {
    "test": "test"
  },
  "scripts": {
    "test": "mocha",
    "start": "bin/www"
  },
  "repository": {
    "type": "git",
    "url": "https://github.com/simonrenoult/octo-day-1"
  },
  "author": "SRE & FJA",
  "license": "ISC"
}

package.json

$ npm install hapi

Install local package

Install global package

$ npm install -g nodemon

$ npm install --save hapi

Save as project dependency

Save as dev dependency

$ npm install --save-dev mocha

$ npm adduser

Setup user

Publish!

$ npm publish

"Hello world!" server

const http = require('http')
const PORT = 8080

function handleRequest(request, response){
    response.end('It Works!! Path Hit: ' + request.url)
}

const server = http.createServer(handleRequest)

server.listen(PORT, function(){
    console.log("Server listening on: http://localhost:%s", PORT)
});

$ node server.js

Run the server

Hello world!

Additional resources

Official website:

Node.js

Learn:

Practice: