Mastering TypeScript: From Basics to Advanced

TypeScript has become an essential tool in modern web development. Let's explore its powerful features and learn how to leverage them effectively.

Why TypeScript?

TypeScript adds static typing to JavaScript, providing:

• Type Safety - Catch errors at compile time
• Better IDE Support - Intelligent code completion
• Refactoring Confidence - Safely rename and restructure code
• Documentation - Types serve as inline documentation

Basic Types

Understanding TypeScript starts with its type system:

// Primitive types
let name: string = "John"
let age: number = 30
let isActive: boolean = true

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

// Objects
interface User {
  id: number
  name: string
  email?: string // Optional property
}

Advanced Types

TypeScript's type system is incredibly powerful:

Union Types

type Status = "pending" | "active" | "completed"
let currentStatus: Status = "active"

Generics

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

const result = identity<string>("hello") // Type is string

Utility Types

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

type PartialUser = Partial<User> // All properties optional
type ReadonlyUser = Readonly<User> // All properties readonly

Best Practices

1. Use strict mode - Enable all strict type checking options
2. Avoid any - Use unknown when type is truly unknown
3. Prefer interfaces - Use interfaces for object shapes
4. Use const assertions - For literal types
5. Leverage type inference - Let TypeScript infer when obvious

Conclusion

TypeScript is more than just JavaScript with types. It's a powerful tool that helps you write better, more maintainable code. Start small, gradually adopt more features, and watch your code quality improve!