TypeScript Beginner to Advanced Guide

What is TypeScript

TypeScript is a superset of JavaScript developed to add static typing. This means errors can be caught during development instead of at runtime. Any valid JavaScript code is also valid TypeScript code.

Why TypeScript Was Created

As JavaScript applications grew larger, maintaining code became difficult. TypeScript was created to improve reliability, readability, refactoring, and tooling support for large projects.

How TypeScript Works

TypeScript code is written in files with a .ts extension. The TypeScript compiler converts this code into plain JavaScript, which can run in browsers or servers.

Install TypeScript

npm install -g typescript
tsc --init

Basic Types and Variables

TypeScript allows explicit type definitions for variables. This improves readability and prevents incorrect assignments.

let username: string = "Rahul";
let age: number = 25;
let isLoggedIn: boolean = true;

let scores: number[] = [80, 85, 90];

Advanced TypeScript Concepts

Advanced features include generics, union types, intersection types, and utility types. These help create reusable and scalable code.

function wrapValue<T>(value: T): T {
  return value
}

let userId: number | string

Common Problems Beginners Face

Many beginners struggle when starting with TypeScript due to misunderstanding types and configuration.

React Performance OptimizationJavaScript Fundamentals

• Overusing the any type
• Confusion between interfaces and types
• Type errors caused by incorrect configuration
• Difficulty understanding compiler errors

Best Practices

Following best practices improves code quality and maintainability.

• Enable strict mode in tsconfig
• Avoid using any
• Use interfaces for object shapes
• Define return types for functions