TypeScrpt basics

+========= What is TypeScrpt? ==========+

Typescript is not entirely new language, it's a super set of JavaScript. that means any valid JS code is also valid typescript code.

Additional feature : -

-->     Strong Typing / static typing,

-->     Object oriented features

( class, interfaces, constructors, access modified like public and private, fills, Properties, Generics and so on. )

-->     Compile time errors

-->     great tooling (i like Intelligence that we get in code editors)

-->     

Typescript is a super set of JavaScript 

Many Browser Transpile Our TS code, into JS.

++========= Use full Commands below ============++

```

npm install -g typescript ( Install typescript Globally )

tsc -v                ( show version )

touch main.ts ( creating new file )

code main.ts ( open in VScode )

tsc main.ts                 ( Compailing into main.js )

node main.ts                 ( run main.js )

```

++========= Declaring Variables ============++

Declearing a variable

let a: number;

let b: boolen;

let c: string;

let d: any;

let e: number[] = [1,2,3];

let f: any[] = [1, true, 'a', false];

const ColorRed = 0;

const ColorGreen = 1;

const ColorBlue = 2;

enum Color {purple = 0, Ra = 1, Green=2, Blue=3};

let BackgroundColor = Color.red;

++========= Type Assertions ============++

let message;

message = "abc";

let endsWithC = (<string>message).endsWith('c');

let alternativeway = (message as string).endsWith('c');

++========= Arrow Function ============++

//in javascripct

let log = function(message){

console.log(message);

}

// in TypeScript

let dolog = (message) => console.log(message);

<!-- we will call this in c# Lamb expresstion -->

<!-- anther way to write if multiple lines-->

let dolog = message => console.log(message);

let dolog = () => console.log();

let doLog = (message) => {

console.doLog(message);

}

++========= Interface | Custom types ============++

interface Point{

x: number,

y: number

}

<!-- use all ways Caps at interface Point -->

let drawPoint = (point: Point) = > {

<!-- -->

}

drawPoint({

x:4,

y:5

})

++========= Classes ============++

class Point {

x: number;

y: number;

draw(){

}

getDitance(anther:point){

}

}

++========= Objects ============++

<!-- create object.ts -->

<!-- touch obejts.ts -->

class Point {

x: number;

y: number;

draw(){

console.log("X: "+ this.x + ", y: "+ this.y);

}

getDistance(anther:Point){

}

}

let point = new Point();

point.x = 1;

point.y = 2;

point.draw();

<!-- runing commands -->

tsc object.ts && node object.js

result: x: 1, y:2

++========= Constructors ============++

class Point{

x: number;

y: number;

constructor(x?: number, y?:number){

this.x = x;

this.y = y;

}

draw(){

console.log("X: "+ this.x + ", y: "+ this.y);

}

getDistance(){

}

}

let point = new Point();

point.draw();

++========= Access Modifiers ============++

---> Public

---> private

---> protected

class Point{

private x:number;

private y:number;

}

++========= Access Modifiers with constructors Parameters ============++

class Point {

constructor (private x?: number, private y?: number) {

}

draw(){

console.log('x:'+ this.x + 'y:'+ this.y);

}

}

let point = new Point(1,2);

point.draw();

++========= Properties ============++

class Point {

constructor(private x?: number, private y?: number){

}

console.log('x:'+this.x+ "y:"+this.y);

get x(){

return this.x;

}

set x(value){

if(value < 0 )

throw new Error("value cannot be less then 0");

this.x = value;

}

}

let point = new Point();

let x = point.x;

point.x = 10;

point.draw();

++========= Modules ============++

file1.ts

export class Point {

constructors(private x?: number, private y?:number){

}

draw(){

console.log('x:'+this.x+ "y:"+this.y);

}

}

file2.ts

import { point } from './point';

let point = new Point();