Today's quote

I AM NOT DISCOURAGED BECAUSE EVERY WRONG ATTEMPT DISCARDED IS A STEP FORWARD

~ Thomas Edison

Some facts about TypeScript

TypeScript was developed by Microsoft about 8 years ago (first public release: 1 October 2012)
TypeScript is a superset of JavaScript, which means that every valid JavaScript code is a valid TypeScript code
TypeScript is written in TypeScript. That's called recursion
Morever, TypeScript source code is available on GitHub with 8.7k+ forks and 65.2k+ stars ⭐
TypeScript is compiled to JavaScript
C# and TypeScript were developed by the same developer, Anders Hejlsberg

Now let's talk about the real stuff.

Why should you learn TypeScript?🤔

1. TypeScript provides you with types in JavaScript.

What does that mean?

JavaScript not provide you to define the type of variable you want while declaring it. The type keeps changing according to the value assigned to it.

But using TypeScript you have this feature

var hello:String = "Hello World";

var hello = "Hello World";

TypeScript Compiler compiles your *.ts file and checks for any errors in types. If you try to assign another type of value to a variable, then your TypeScript Compiler will surely give you an error.

Means if you write this code

var hello:String = "Hello World";
hello = 123;

Then you will get this error Type 'number' is not assignable to 'String'

Looks like a nice catch, isn't it

Im different words TypeScript is strongly typed language

2. TypeScript is Open Source

What makes a developer feel more proud then using an Open Source software? Nothing, Yeah!😇

3. Huge community

TypeScript has a huge community of developers on Stackoverflow and other sites. So, if you will ever fall in some problem, there will be always someone to help you out.

4. Better for huge projects

TypeScript is mainly used for large projects becuase it provides much better exception catches.

Some awesome examples of Open Sourced TypeScript projects:

5. Much more like other popular languages like C#, C++, or Java

Many people feel that TypeScript is much related to C# because TypeScript's syntax is much more similar.

A default support for enum

Yeah! You heard that right. TypeScript has a default support for enum classes which is very much similiar to that of C++.

enum S {
    NO = 0,
    YES = 1
}

Unions in TypeScript

If you have learnt C or C++, then you may be probably familiar with union types.

Unions in TypeScript are somewhat different from them. In TypeScript union is a variable with multiple types.

Example of union in TypeScript

let myVar : string | number;        //Variable with union type declaration

myVar = 100;            //OK
myVar = 'Lokesh';       //OK

myVar = true;           //Error - boolean not allowed

TypeScript Tutorial

We currently read why should you learn TypeScript , now let us code some TypeScript

Before you start with this tutorial make sure you know some basics of

JavaScript
HTML
CSS

Installing TypeScript

Before running and/or compiling TypeScript you need to install the TypeScript Compiler first. You have mainly 3 ways to use TypeScript

Installing TypeScript package 📦 using npm

nodejs logo

First download and install node.js from nodejs.org
Open a fresh new terminal and run node -v. If you get something like v14.14.0, congrats your installation is successful
After the installation is successful run npm install -g typescript
Check your TypeScript installation by running tsc -v

Using TypeScript from your browser

Just open TypeScript Playground on your browser

Installing plug-in/extension directly in your IDE

Search for TypeScript Compiler in your IDE, check if you get one, if not follow any above method. If you are using Visual Studio IDE, then you should get the TypeScript extension on Marketplace

Coding our TypeScript file

I strongly recommend you to use a Code Editor during this tutorial, it will give you syntax highlighting, which will help you a lot. Incase you don't have one get any one of these

Let's create a new TS file

Create a new blank folder, and open your code editor there. In your editor create a new file with any name you want and at the end .ts. This .ts file is your TypeScript source file.

I gave the name index.html.

Let's write some code

Open your TypeScript file. And type the following code

const date:Date = new Date();
const hour:Number = date.getHours();
const minute:Number = date.getMinutes();
const seconds:Number = date.getSeconds();
console.log(`The time is ${hour} : ${minute} : ${seconds}`)

This simple TypeScript program will give you the current time.

Compiling TypeScript

Browsers and other JavaScript engines can't run TypeScript, you need to compile it first.

Let's compile it.

Open your terminal in the Current Directory.

Quick Bonus Tip: If you are using VS Code, you can open terminal directly by dragging from the top of the bottom status bar.

To compile your TypeScript file run tsc <filename> in your terminal. After the compilation, you should get the *.js file in the same directory with the same name.

If you get any errors while compiling TypeScript, make sure you did it correctly.

Running the compiled JavaScript.

You can run your compiled JavaScript in either your browser console or node.js

To run in node.js

Run node <filename.js> in your terminal. Hurray!! You learnt some basics of TypeScript.

Some recommended YouTube videos you must watch

https://www.youtube.com/watch?v=BwuLxPH8IDs

Now, if you have read this far consider following me on Twitter(@CodingThunder)

If you liked this article, don't forget to like❤️, share and drop your valuable suggestions in the comments section below.