TypeScript Hindi Tutorial: #3 - All Data Types Explained

What is DataTypes?

  1. Primitive Types
  2. Object Types
  3. Special Types
  4. Advanced Types
  5. Function Types


🔹 Basic Data Types


var userName:string="Anil sidhu"
var age:number=30;
var male:boolean=true;


number : Represents all numbers (integers, floats, hex, binary, octal).

let age: number = 25;
let pi: number = 3.14;
let hex: number = 0xff; // hexadecimal


string : Used for text (with single, double, or backticks for template strings).

let name: string = "Arjun";
let greeting: string = `Hello, ${name}!`;


boolean : Represents true/false values.

let isActive: boolean = true;
let isAdmin: boolean = false;


null & undefined: Special types with only one value each.
let n: null = null;
let u: undefined = undefined;


🔹 Special Types


any : Can hold any type (not recommended unless necessary).

let randomValue: any = 10;
randomValue = "Hello";
randomValue = true;


unknown: Similar to any, but safer (forces type-checking before usage).


let value: unknown = "hello";
if (typeof value === "string") {
console.log(value.toUpperCase());
}


void: Usually for functions that don’t return anything.

function logMessage(msg: string): void {
console.log(msg);
}



never: Represents values that never occur (e.g., function that always throws error).

function throwError(message: string): never {
throw new Error(message);
}


🔹 Object & Collection Types

object: Represents non-primitive types.
let person: { name: string; age: number } = { name: "Aman", age: 22 };


Arrays: Can be written as type[] or Array<type>.

let numbers: number[] = [1, 2, 3];
let fruits: Array<string> = ["apple", "banana"];


Tuples: Fixed length & order array with specific types.

let user: [number, string] = [1, "Raj"];


Enums:A set of named constants.


enum Direction { Up, Down, Left, Right }
let move: Direction = Direction.Up;


🔹 Advanced Types


Union (|) : Variable can be multiple types.


let id: number | string;
id = 101;
id = "abc";


Intersection (&): Combines multiple types into one.


type Person = { name: string };
type Employee = { id: number };
type Staff = Person & Employee;

let emp: Staff = { name: "Ravi", id: 101 };




Type Aliases:Create your own type shortcuts.

type ID = number | string;
let userId: ID = "U123";


Literal Types:Restrict values to exact strings/numbers.


let status: "success" | "error" | "loading";
status = "success";



✅ In short:


Basic types: number, string, boolean


Special types: any, unknown, void, never


Data structures: object, array, tuple, enum


Advanced: union, intersection, type alias, literals