npm install -g typescript

// Basic types
let name: string = "TechYouHigh";
let age: number = 25;
let isActive: boolean = true;

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

// Tuple
let coordinates: [number, number] = [10, 20];

// Any (to avoid)
let variable: any = "anything";

interface User {
  id: number;
  name: string;
  email: string;
  age?: number; // Optional property
  readonly createdAt: Date; // Read-only
}

const user: User = {
  id: 1,
  name: "John Doe",
  email: "john@example.com",
  createdAt: new Date(),
};

// Type alias
type ID = string | number;
type Status = "active" | "inactive" | "suspended";

// Union types
function showId(id: ID) {
  console.log(`ID: ${id}`);
}

// Literal types
let status: Status = "active";

// Function with types
function add(a: number, b: number): number {
  return a + b;
}

// Function with optional parameters
function greet(name: string, title?: string): string {
  return title ? `${title} ${name}` : name;
}

// Function with default parameters
function createUser(name: string, role: string = "user") {
  return { name, role };
}

// Function type
type MathOperation = (a: number, b: number) => number;

const multiply: MathOperation = (a, b) => a * b;

// Generic function
function firstElement<T>(array: T[]): T | undefined {
  return array[0];
}

const firstNumber = firstElement([1, 2, 3]); // number
const firstText = firstElement(["a", "b"]); // string

// Generic interface
interface Response<T> {
  data: T;
  status: number;
  message: string;
}

const userResponse: Response<User> = {
  data: user,
  status: 200,
  message: "Success",
};

class Person {
  private id: number;
  public name: string;
  protected age: number;

  constructor(id: number, name: string, age: number) {
    this.id = id;
    this.name = name;
    this.age = age;
  }

  introduce(): string {
    return `My name is ${this.name}`;
  }

  get identifier(): number {
    return this.id;
  }
}

class Employee extends Person {
  constructor(id: number, name: string, age: number, public position: string) {
    super(id, name, age);
  }

  introduce(): string {
    return `${super.introduce()} and I am a ${this.position}`;
  }
}

// Partial: makes all properties optional
type PartialUser = Partial<User>;

// Required: makes all properties required
type CompleteUser = Required<User>;

// Pick: selects certain properties
type BasicUser = Pick<User, "id" | "name">;

// Omit: excludes certain properties
type UserWithoutEmail = Omit<User, "email">;

// Record: creates an object type
type Roles = Record<string, string[]>;
const permissions: Roles = {
  admin: ["read", "write", "delete"],
  user: ["read"],
};

{
  "compilerOptions": {
    "target": "ES2020",
    "module": "commonjs",
    "strict": true,
    "esModuleInterop": true,
    "skipLibCheck": true,
    "forceConsistentCasingInFileNames": true,
    "outDir": "./dist",
    "rootDir": "./src"
  },
  "include": ["src/**/*"],
  "exclude": ["node_modules"]
}