Node.js Quickstart

Learn the basics of Node.js in 7 easy steps

Step 1 - What is Node?

Node is a runtime that allows you to run JavaScript on the server. Learn more in the how JavaScript works section of this course.

Step 2 - Install Node

Follow these instructions to install NodeJS. This course uses Node version 12, nvm install 12.

Step 3 - Hello world

Create a JavaScript file.

file_type_js index.js 
console.log('hello world')

Run it with node.

command line 
node . # points to index.js

node index.js

Step 4 - Builtins & Globals

Node has several global variables that you should know about:

  • global use it to save global variable throughout the app. Similar to window in the browser.
  • process interact with the current process to information like the OS platform or environment variables.

Step 5 - Events & Emitters

In most cases, you will find yourself listening to events and handling them with callbacks, but you can create your own events with an EventEmitter.

// Create
const { EventEmitter } = require('events');
const eventEmitter = new EventEmitter();

// Handle
eventEmitter.on('lunch', () => {

    console.log('yum 🍣');

});

// Emit
eventEmitter.emit('lunch');
eventEmitter.emit('lunch');

// yum 🍣
// yum 🍣

Step 6 - Work with the File System

Many APIs in Node are callback based.

const { readFile, readFileSync } = require('fs');

// Blocking!
const txt = readFileSync('./hello.txt', 'utf8');
console.log(txt)


// Non-blocking
readFile('./hello.txt', 'utf8', (err, txt) => {
    console.log(txt)
});

// Promise based, also non-blocking
const { readFile } = require('fs').promises;

const txt = await readFile('./hello.txt', 'utf8');

Step 7 - Modules and NPM

A module is just a file that exports its code.

file_type_js cool.js 
module.exports = {
    hello: 'world'
}

Another file can use this code by importing it.

const { hello } = require('./cool.js');

console.log(hello);
// world

Install remote modules by initializing an NPM project.

command line 
npm init -y

npm install express

Build a Full Stack Wep App

Use Express to create an HTTP endpoint

Create an HTML file.

file_type_html home.html 
<html>
<head>
    <title>Hi Mom!</title>
</head>

<body>
    <h1>This is my web app!</h1>
</body>
  1. Use express to build an HTTP endpoint
  2. Read the HTML file
  3. Send it back to the client
file_type_js index.js 
const express = require('express');
const app = express();
const { readFile } = require('fs').promises;

app.get('/', async (request, response) => {

    response.send( await readFile('./home.html', 'utf8') );

});

app.listen(process.env.PORT || 3000, () => console.log(`App available on http://localhost:3000`))

Deploy the app to Google App Engine

Create a Google Cloud account and install the gcloud SDK.

Configure your server.

file_type_light_yaml app.yaml 
runtime: nodejs12

Deploy it.

command line 
gcloud app deploy

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