What is it?
Built on Google Chrome’s V8, open-source JS Engine
Compiles JS direct to machine code made executable for the computer
JS runtime
Simply put: Event-based,non-blocking,asynchronous I/O runtime using google v8 JS engine + libuv library
Installation
Installation of multiple versions to switch back and forth
how to install multiple version using nvm
check for installation with node -v
should result in a version number
check for proof of life
Node.js support for modern JS
Since only one time is target for V8 engine you can write JS with the most current syntax and shouldn’t have to worry about compatibility issues.
npm-the JS package manager
To check:
npm -vTo install:
npm install -g jshint to instal jshint package globally on systemRun linting on file:
example jshint esversion: 6 */
fix ES6 errors by adding /* jshint esversion: 6 */
installing packages **locally to project instead of globally**
npm init -y to autopopulate a package.json file in the designated folder
npm install lodash --save to save as a project dependency
create a test.js fild and add
`` const _ = require(‘lodash’);
const arr = [0, 1, false, 2, '', 3];
console.log(_.compact(arr));
``
run script in terminal with node test.js
should see appropriate output of [1, 2, 3 ]
working with package.json file
inside of test directory should be a folder called node_modules where npm saves lodash and the libraries which it depends on.
node_modules shouldn’t be checked in to version control
re-create node_modules anytime by running npm install from project root
What is Node.js used for?
Node.js is most often used for installing (npm) and running (node) tools for modern JS app.
Let’s us run JS on server
how?
Node.js = single-threaded
Event-driven
Node = asynchronous (non-blocking) if event request is blocked by I/O operation and will register callback before next event processing.
refer to site for visual of Node.js event loop
ex:
test it by creating a servertest.js
`` const http = require(‘http’);
http.createServer((request, response) => {
response.writeHead(200);
response.end('Hello, World!');
}).listen(3000);
console.log('Server running on http://localhost:3000');
``
then run it with node servertest.js
got to http://localhost:3000 to check for proof of life
Most suitable uses for node.js
real time apps for interaction/collaboration
building APIs
data streaming
Its advantages
Speed
Scalability
Ability to do everything with one language
understands JSON
As a scripting language, automating frequent/error prone tasks
create a command line tool