Node.js handbook

Presented by Arnaud Buchholz
Inspired from The definitive Node.js handbook from Flavio Copes
Presentation made with Reveal.js

Agenda

Introduction to Node.js

Overview

• Node.js is a runtime environment for JavaScript that runs on the server
• GitHub repository has more than 58k stars
• Node.js is built on top of the Google Chrome V8 JavaScript engine

It's fast, simple & asynchronous

JavaScript allows to create asynchronous and non-blocking code in a very simple way, by using a single thread, callback functions and event-driven programming.

It's powerful

This allows Node.js to handle thousands of concurrent connections with a single server without introducing the burden of managing threads concurrency.

A vast ecosystem

With its simple structure, the node package manager (npm) helped the ecosystem of Node.js proliferate.

Now the npm registry hosts almost 500,000 open source packages you can freely use.

Hello World

History 1/2

History 2/2

Why is it named Node.js ?

Node.js & ES6 Basics

Installation

• Download
• Windows, macOS, Linux or even source code
• Choose between LTS or Latest

Running

• In a command line prompt
• Execute any script:
  node script.js
• Or use the interactive Read-Eval-Print-Loop:
  node
  It offers an autocompletion feature, try with global.

JavaScript

• Node.js supports the JavaScript you know
• It also supports future evolutions / variants of the language
  • Either natively, such as most ES6 features
  • Or using transpilers: Babel, TypeScript...

ES6 JavaScript

ES6 Samples

ES6 const

• const is for constant assignment

• const is not for constant value

ES6 let

• let introduces block scoping to JavaScript
• let does not benefit from hoisting

ES6 Arrow functions

• Compact alternative for function
• No own bindings (this, arguments...)
• Not for constructors or methods
• Ideal for callbacks

ES6 Arrow functions

ES6 Template Literals

• Compact alternative for string with embedded values
• Supports Multi-line

ES6 Spread syntax

• When used on the right of an assignment,
  ... expands an iterable object into a list of parameters or elements

ES6 Spread syntax

ES6 Destructuring Assignment

• Assign values from arrays, or properties from objects, into distinct variables
• When used on the left of an assignment,
  ... is a collect syntax^*

ES6 Destructuring Assignment

ES6 Promises , async and await

• async functions are asynchronous and implicitly returns a promise
• The await operator is used to wait for a promise

ES6 Promises , async and await

Other ES6 features

• Default parameters

const multiply = (a, b = 1) => a * b
console.log(multiply(5)) // 5

• Classes

class Rectangle extends Shape {
	constructor (width, height, filled = false, color = "black") {
		super(filled, color)
		this.width = width
		this.height = height
	}

	get area () {
		return this.width * this.height
	}
}

Other ES6 features

• Modules: import
• Generator function: function*

Node.js as a Host

• Node.js has its own environment
  • The global context object is global


• Additional features are available with require
  • Either for standard modules
  • Or for installed packages (NPM)

Node.js as a Command Line

• The current Node.js instance information is available through the process object
  • Environment variables are on the process.env dictionary
  • Command line arguments are in the process.argv array
• console APIs output on the command line

Node.js as a Command Line

Reading from the command line is not straightforward

Exercise 1: Explorer

Prerequesites

Use Clone or download button

A server to scan any folder

Error management

File system API

• Node.js is designed to run on any environment
• Operating system operations are abstracted

fs module

Check Node.js documentation of fs.statSync

Step 1: synchronous readdir

Step 2: asynchronous readdir

Step 3: asynchronous readdir with promises