Node.js Tutorial

What is the syntax like?

Well, everything you already know with JavaScript can be played here, except for the DOM, which if you don't know, includes interacting with a website.

For example we can do some basic console.logs() in Node.js

const x = 6;

// Console commands work as normal
console.log('x is ' + 6); // Returns 'x is 6'

//But with ES5 you can do this:
console.log(`x is ${x}`); // Returns 'x is 6'

Ok, but why Node.js

Well, first off, if you want to know why not to use python, I won't say anything, but if you are here because you don't know the difference between the browser js, then continue on.

Node.js makes everything come together. It's a server, which basically controls a bunch of people. Chat rooms send a message to the server, which sends it to everyone else.

But it all starts here...

Node.js has something called a module

4 concepts to remember about modules

A module must be imported
Modules make Node.js work not like browser js
Modules can make coding cleaner, resulting in more files and folders
You can make a module very easily

Ok, how do you import a module

Well lets use the old fashion way because repl needs to update to node 14 for other things.

Below is how you import a module

const variableToHoldContentOfModule = require('module name as it should be')

Can we import a module as an example?

Yeah ok, lets use the OS module

It can help with determining what module to use.

// Import the module, using require syntax

let os = require('os');
//now that we have the os module, we can use the docs to help us find out our platform. Do this by tacking on .platform() to it.

console.log(`Your platform is ${os.platform()}`)
//now on repl it will be weird to some, as it says Linux, but thats because repl uses a virtual machine built on linux.

How do we make our own module?

Well modules are just js files that work with the server. Try going into module.js at this time, or making it if you are following by yourself.

In there, we added the following code:

// Write some code that you want to share with index.js, 

let x = 'some random text to export';

function add(x, y) {
  return x + y; //simle add function
}

function sub(x, y) {
  return x - y; //simle subtract function
}

As of right now these functions and variables are local to the file, so to make them public, you do the following after everything was declared. It is usually the last thing in a file.

module.exports = {
  addFunction: add,
  subFunction: sub,
  randomText: x
}

Come back to index.js and import it

//Node already knows its a js file so you dont need the extension

const moduleWeGot = require('./module');

// the "./" refers to the root directory

// Time to see our options:

console.log(moduleWeGot);

We see this:

{
  addFunction: [Function: add],
  subFunction: [Function: sub],
  randomText: 'some random text to export'
}

Our data is there, so now we can just get them with some dot notation.

moduleWeGot.addFunction(5, 4); //returns 9

There is an easier way to get the module though

const { addFunction, subFunction, randomText } = require('./module');

Then use the function as follows

addFunction(5, 66); //Returns 71