javascript-node.md

Node Notes

• Can use ES6, Typescript to write apps
• Non-blocking commands
• Callback heavy
• Each incoming connection is a small heap allocation

npm commands:

• npm init
• npm i package --save

https://gist.github.com/martinheidegger/5554941

Libraries

RESTful Libraries

• RESTify - http://mcavage.me/node-restify/
• Unirest - http://unirest.io/nodejs.html

Command Line

• Commander
• Option Parsing - https://github.com/substack/node-optimist

Webapp Framework:

• Express
• hapi.js

Process Management:

• pm2

Commonly Used Constructs

Not exclusive to Node at all, but commonly used constructs.

• const for initial module imports
• let/var difference in terms of scoping - let is scoped to the nearest block rather than function
• ES6 Arrow Function Expression

RESTful Calls with Unirest

Example get request:

unirest.get(url)
    .set('Accept', 'application/json')
    .set('Content-Type', 'application/json')
    .set('User-Agent', userAgent)
    .end(function (response) {
        console.log(response.body['response']);
    }

JSON display:

JSON.stringify(baseResponse, null, 2)

Networking

HTTP Server

Create a simple HTTP server with:

var http = require("http");

http.createServer(function(request, response) {
  response.writeHead(200, {"Content-Type": "text/plain"});
  response.write("Hello World");
  response.end();
}).listen(8888);

TCP Server

Connect with curl localhost:8000 for the following TCP server:

var net = require('net');
var port = 8000;
 
net.createServer(
  function (stream) {
    stream.write('hello\r\n');
 
    stream.on('end',
      function () {
        stream.end('goodbye\r\n');
      }
    );
 
    stream.pipe(stream);
  }
).listen(port);

console.log("Created TCP server on port " + port);