playing Node.js: 1. basic concepts

18 Oct 2012

These days, I wanna have a look at the hot and smart technology: Node.js. So I’d like to make some notes and share some useful resources.

Node.js

What’s Node.js?

Javascript on the server side.

What’s npm?

The package manager for Node.js. npm for Node.js is as apt-get for Ubuntu.

How to install it?

I’m not talking about how to do it in Windows, because it’s bringing ourselves into troubles. Use one of the techniques from gist: 579814 is just good and ok. After following that, npm and node shoule be avaiable as the command in the shell.

What’s a package.json file? And what’s a node_modules folder?

Every Node.js project should provide one of these. It describes the dependencies and some other information of the project. See one example. node_modules is the floder of the local dependency files.

What’s the module, require and exports?

There are two excelent posts explaining them. Node.js, Require and Exports, Node.js, Module.Exports and Organizing Express.js Routes. The follwing should be read before reading the second post here.

CoffeeScript

What’s CoffeeScript?

CoffeeScript is a little language that compiles into JavaScript. It provides a simplified way to write javascript without the annoying from awkward braces and semicolons and othe stuff from the original javascript.

Why should I use it?

It’s the good part of javascript.

How to use it?

npm install coffee -g so coffee is the command line. See Installing for more information. It can be used on client side too.

How to transer between CoffeeScript and javascript?

Command line can be used. However, official website provide an in-time translator from CoffeeScript to javascript, which is good for development. And there’s an unofficial project, called js2coffee, whose website provide an in-time translator from javascript to CoffeeScript! (However, the latter one may occur some mistakes, and the result should be checked on the first site…)

Express

What’s it?

A framework for devloping Node.js websites.

Install?

npm install express@3.x -g for global usage. Create a folde and run express --css stylus to get a hello world example. Then npm install to install the dependencies locally. Run node app to view the website!

What’s a “middleware”?

“Middleware” is an important concept for Express framework, and Connect, the framework that Express is based on. In short, a request sent to Express apps (or/and the response) is handled, modified, ‘filtered’ by the middlewares, in order.

In fact, I think Node.js is still young, and its concepts are unfamiliar to most of us. It’s good toy, however it should be carefully considered if we want to use it in production.