TypeScript

TypeScript is a statically typed superset of JavaScript developed and maintained by Microsoft. It adds optional static typing and modern features to JavaScript, enabling developers to build more reliable, maintainable, and scalable applications.

Key Features

Static Typing

TypeScript allows developers to declare variable and function types for better predictability.

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

Type Inference

TypeScript can automatically infer types without explicit annotations.

let count = 10; // inferred as number
// count = "ten"; Error: Type 'string' is not assignable to type 'number'

Modern JavaScript Support

TypeScript supports the latest ECMAScript features while compiling down to plain JavaScript.

// Using optional chaining (modern JavaScript feature)
const user = { profile: { name: "Ashwin" } };
console.log(user?.profile?.name); // "Ashwin"

Interfaces and Types

Interfaces help define contracts for objects, improving maintainability.

interface User {
  id: number;
  name: string;
  isActive: boolean;
}
 
const ashwin: User = {
  id: 1,
  name: "Ashwin",
  isActive: true
};

Classes and OOP

TypeScript enhances object-oriented programming with features like access modifiers.

class Person {
  private name: string;
 
  constructor(name: string) {
    this.name = name;
  }
 
  greet(): string {
    return `Hello, my name is ${this.name}`;
  }
}
 
const p = new Person("Ashwin");
console.log(p.greet()); // Hello, my name is Ashwin

Tooling and Editor Support

TypeScript integrates deeply with IDEs like VS Code, providing autocompletion, refactoring, and error highlighting.

Advantages

• Reduces bugs through type safety and compile-time checks
• Enhances productivity with editor tooling and auto-completion
• Improves maintainability for large-scale applications
• Works seamlessly with existing JavaScript projects

Purpose

TypeScript aims to make large-scale application development more predictable and robust by extending JavaScript with static typing and modern programming constructs. It is widely used in frameworks like React for building reliable Single Page Applications, and integrates smoothly with build tools such as Vite.