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Basic Types#

Define specific types#

let username: string = "kushal101";
let age: number = 25;
let isActive: boolean = true;

Define array#

let numbers: number[] = [1, 2, 3];
let strings: Array<string> = ["a", "b"];

Define tuple#

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

Define enum#

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

enum Status { Pending = "PENDING", Approved = "APPROVED" }

Define object type#

let person: { name: string; age: number } = {
  name: "John",
  age: 30
};

Define union type (one of multiple types)#

let id: string | number;

Define intersection type (combine types)#

type Staff = Person & Employee;

Define type alias#

type ID = string | number;
type Point = { x: number; y: number };

Define literal type#

let direction: "left" | "right";

Type assertion (casting)#

let strLength: number = (someValue as string).length;