Basics.md

Basics

What is Typescript

• Typescript is just a type system.
• We're just writing javascript code including types.
• Browser don't understand typescript.

Why we're using it?

• Helps us to catch errors during development.
• Adding type annotation for analyze the code.

How typescript works in development?

• Typescript code that we written will compile by a Typescript compiler and convert it to javascript.
• Here is package we're using for compilation

Notes:

• No effects of how our code is getting executed.
• There is no performance optimization in any logic we made.

Types

• There are two types of Types in typescript
  • Primitive types
    • number
    • boolean
    • void
    • undefined
    • string
    • symbol
    • null
  • Object types
    • functions
    • arrays
    • classes
    • objects

Annotations

• It's a code, we can tell typescript what type of value a variable will refer to

Typescript examples

// number
let grapes: number = 12;
// string
let name: string = "John Doe";
// boolean
let hasValue: boolean = true;
// null
let isnull: null = null;
// undefined
let isundefined: undefined = undefined;
// Date
let now: Date = new Date(); 
// Array
let cart: string[] = ['apples', 'grapes', 'toothbrush'];
// Function
let newFunction: void = (i: number) => {
    console.log(i)
    // not returning anything
}