TypeScript: Why JavaScript Developers Need Types

Introduction

TypeScript is a superset of JavaScript developed by Microsoft.

It adds static typing to JavaScript, helping developers catch errors before code runs.

Why TypeScript?

Consider this JavaScript code:

function add(a, b) {
  return a + b;
}

TypeScript catches many mistakes during development.

Installing TypeScript

npm install -g typescript

Verify installation:

tsc --version

Basic Types

let name: string = "John";
let age: number = 25;
let active: boolean = true;

Functions with Types

function add(a: number, b: number): number {
  return a + b;
}

Arrays

const numbers: number[] = [1, 2, 3];

Interfaces

interface User {
  id: number;
  name: string;
  email: string;
}

Usage:

const user: User = {
  id: 1,
  name: "John",
  email: "john@example.com"
};

TypeScript Compilation

Compile:

tsc app.ts

Benefits of TypeScript