Intro to Node

Node.js® is a JavaScript runtime built on Chrome's V8 JavaScript engine. Node.js uses an event-driven, non-blocking I/O model that makes it lightweight and efficient. Node.js' package ecosystem, npm, is the largest ecosystem of open source libraries in the world.

A node_modeule is basically a lego block of code. Everything in a node application is modular, meaning it is made up of many different smaller parts that work towards the end functionality.

NPM stands for Node Package Manager. It's just a tool that allows us to easily acces the node module ecosystem and add them to our project. Example node_module: Moment.js

Every node app has a package.json , which is the master file that keeps track of all node maodules your project cares about.

to add a package.json to your project, run the commmandnpm init , and accept all defaults.

---

git add -A

git commit -m "introductory definitions for node"

git push origin master

---

Node HTTP Server

We used the node module HTTP to build a simple web server, that we can then run and connect to using the web address: http://localhost:3000/ . To run the server use the command node index.js

var http = require('http');

http.createServer(function(request, response){
  response.writeHead(200, {'Content-Type': 'text/plain'});
  response.end('Hello world!');
}).listen(3000, function(){
  console.log('App is listening on port 3000')
});

---

Express Web server

Express API To add express node module to our application: npm install --save express To ensure it was added succesfully, check your package.json for:

"dependencies": {
  "express": "4.15.3"
:}

This also gives us a ton of code we do not care to track in our Github, in the node_modules/ folder. To ignore this code;

touch .gitignore add node_module/ to .gitignore

---

Nodemon

nodemon will watch our files automatically and restart our server so we don't have to do it manually. nodemon index.js -> to start server how to install: sudo npm install -g nodemon

---

POSTMAN

When using postman you have to make sure that your names match in on your as well as in postman.

app.post('/fish', function(req, res){

  var type = req.body.type;
  var length = req.body.length;
  var color = req.body.color;

  var fish = {type: type, length: length, color: color};

  res.json(fish); ```