10 Essential TypeScript Tips for Beginners

As someone who’s spent countless hours working with TypeScript, I’ve gathered some invaluable tips that I wish I’d known when starting out. Let’s dive into ten essential TypeScript tips that will help you write better, safer code from day one.

1. Enable Strict Mode from the Start

One of the best decisions you can make when beginning with TypeScript is to enable strict mode in your tsconfig.json. While it might seem intimidating at first, it’s like having a strict but helpful mentor watching over your code:

{
  "compilerOptions": {
    "strict": true
  }
}

This single setting helps catch common mistakes and enforces better typing practices. Trust me, your future self will thank you!

2. Type Inference Is Your Friend

Instead of explicitly typing everything, let TypeScript’s powerful type inference do the heavy lifting:

// Instead of this
const message: string = "Hello";

// Do this
const message = "Hello"; // TypeScript knows it's a string!

3. Understanding the ‘any’ Type Trap

Think of ‘any’ as an escape hatch - it’s tempting to use it when you’re stuck, but it defeats the purpose of using TypeScript. Instead, consider using ‘unknown’ for better type safety:

// Avoid
function processData(data: any) {
  // This is unsafe!
}

// Better
function processData(data: unknown) {
  if (typeof data === "string") {
    // TypeScript knows it's safe now
    return data.toUpperCase();
  }
}

4. Interface vs. Type: Making the Right Choice

Interfaces and types are similar, but each has its sweet spot. Interfaces are great for defining object shapes and can be extended, while types are perfect for unions and complex types:

// Interface for objects
interface User {
  name: string;
  age: number;
}

// Type for unions
type Status = "pending" | "approved" | "rejected";

5. Mastering Optional Properties

Use the ? operator for optional properties instead of allowing undefined:

interface Profile {
  name: string;
  bio?: string; // Optional
}

6. Leveraging Union Types

Union types are incredibly powerful for handling multiple possible types:

function handleResponse(response: string | number) {
  if (typeof response === "string") {
    console.log(response.toUpperCase());
  } else {
    console.log(response.toFixed(2));
  }
}

7. Type Assertions When Necessary

Sometimes you know more about a type than TypeScript does. Use type assertions wisely:

const canvas = document.getElementById("myCanvas") as HTMLCanvasElement;

8. Generics for Reusable Code

Generics might seem complex, but they’re worth learning for creating flexible, reusable code:

function firstElement\<T\>(arr: T[]): T | undefined {
  return arr[0];
}

9. Readonly for Immutability

Use readonly to prevent accidental modifications:

interface Config {
  readonly apiKey: string;
  readonly baseUrl: string;
}

10. Utilize Built-in Utility Types

TypeScript comes with powerful utility types that can save you time:

type UserPartial = Partial<User>; // All properties become optional
type UserReadonly = Readonly<User>; // All properties become readonly

Remember, TypeScript is here to help, not to complicate your development process. Start with these fundamentals, and you’ll be writing safer, more maintainable code in no time!