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#TypeScript#Programming#Tips

Essential TypeScript Tips

Useful TypeScript patterns and techniques for writing better code

Essential TypeScript Tips

TypeScript is a powerful tool for building scalable applications. Here are some essential tips to level up your TypeScript game.

Utility Types

TypeScript provides several built-in utility types that can help you manipulate types more effectively:

Partial<T>

Makes all properties optional:
interface User {
  id: number;
  name: string;
  email: string;
}

type PartialUser = Partial<User>; // All properties are optional

Pick<T, K>

Selects a subset of properties:
type UserPreview = Pick<User, 'id' | 'name'>;

Omit<T, K>

Excludes specific properties:
type UserWithoutId = Omit<User, 'id'>;

Discriminated Unions

Use discriminated unions for type-safe handling of different data types:
type Result =
  | { status: 'success'; data: string }
  | { status: 'error'; error: Error }
  | { status: 'loading' };

function handleResult(result: Result) {
  if (result.status === 'success') {
    console.log(result.data); // data is available here
  } else if (result.status === 'error') {
    console.log(result.error); // error is available here
  }
}

Const Assertions

Use
as const
to get the most specific literal types:
const colors = ['red', 'green', 'blue'] as const;
// Type is readonly ['red', 'green', 'blue']

const config = {
  apiUrl: 'https://api.example.com',
  timeout: 5000
} as const;
// Types are inferred as readonly literals

Generics with Constraints

Add constraints to make generics more powerful:
interface HasLength {
  length: number;
}

function getLength<T extends HasLength>(item: T): number {
  return item.length;
}

getLength('hello'); // OK
getLength([1, 2, 3]); // OK
getLength(42); // Error!

Key Takeaways

  • Use utility types to reduce boilerplate
  • Leverage discriminated unions for type safety
  • Use const assertions for literal types
  • Apply generic constraints for better type checking
Happy coding! 🚀
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