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_module 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 access the Node module ecosystem and ad 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 modules your project cares about.

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

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Commit your code

git add -A

git commit -m "push message"

git push origin master

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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 successfully, 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_modules/ to .gitignore

express server

var express = require("express");
var app = express();

app.get("/greeting", function(req, res){
  res.send("Wahoo you found the greeting end point!")
});

app.get("/wazzup", function(req, res){
  res.send("You kind of get this, but not really!")
});


app.listen(3000, function(){
  console.log("Listening on port 3000");
});

Request Parameter -

This is a way to pass data from the URL to the page/ index.js Here is a block of the code for example:

app.get("/greeting/:name", function(req, res){
  var yourName = req.params.name;
  res.send("Nice to meet you "+ yourName)
});

app.get("/greeting/color/:color", function(req, res){
  var favColor = req.params.color;
  res.send("This is your fav color "+ favColor)
});

NodeMon

This makes it so I do not have to node index.js every time to restart the server. It auto updates everytime. I just need to make sure I start the process which each new "session" nodemon index.js

note - - the terminal will continue to run on its own, but if you need to type in the terminal you will need to Control C it and terminate the server. This was confusing at first - I get it now

Adding new endpoints to pass data from form:

here is the JS

app.post("/mtb", function(req, res){
  var brand = req.body.brand;
  var model = req.body.model;
  var build = req.body.build;

  var mtb = {brand: brand, model: model, build: build};
  res.json(mtb);
  console.log("I wants a ", brand, " ",model," with a ",build," build.");
});

Using the req.body.KEY where the KEY is defined right now by the user- we are using Postman to look at this right now. So if I put "brand" as the KEY and "Santa Cruz" as the VALUE the res / var brand would be "Santa Cruz" in the above example.