reading-notes

Node, Express, and APIs

Source: An Introduction to Node.js

What is Node.js

Program to execute JavaScript outside of the browser.
Built on V8 engine– open source JS engine runs runs in Chromium based browsers.

Installing Node.js

Direct from node download page
(Preferred) Using a version manager, NVM, so you can have multiple versions of Node at once.
To check version install
```
node -v
```
To run js file in node
```
node hello.js
```

Package Management w/ NPM

Node is bundled with a package manager, NPM
NPM is the JS package manger, and largest registry
To check version install
```
npm -v
```

To install a package globally

  npm install -g jshint

To install a package locally

  npm init -y
  npm install lodash --save

This process does 2 things:

Creates a package.json file in the directory
- Package.json file describes dependencies, allowing other devs to use NPM to install them
Includes a node_modules folder with relevant files.
- Don’t include in version control.
```
const _ = require('lodash');
```

This specifies which packages are neded in a file

Using Node.js

Many uses: bundling files and dependencies, running tests, code linting, style checking

Run JavaScript on the Server

The biggest use case for Node.js

Node.js is single threaded and event driven
Allows non-blocking processing of actions

Example

hello-world-server.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');

node hello-world-server.js

Browser: http://localhost:3000

Note: Use nodemon to autoreload server changes

Disadvantages

Since Node is single threaded, avoid blocking I/O calls.
Hand off CPU-intensive operations to worker thread

Advantages

Speed / scalability
Use same language for backend / frontend
JSON (same syntax browser <-> server <-> client)

Use Node.js for…

Real time interactions
APIs
Data streaming

Other Uses

Scripting
Cross-platform desktop apps