TypeScript Tips for Better Code

Let’s explore some TypeScript features that can make your code more robust.

Generic Constraints

Here’s how to use generic constraints effectively:

interface HasLength {
  length: number;
}

function logLength<T extends HasLength>(arg: T): number {
  console.log(arg.length);
  return arg.length;
}

// Works with strings
logLength("Hello"); // 5

// Works with arrays
logLength([1, 2, 3]); // 3

// Error: number doesn't have length
logLength(123); // Error!

Utility Types

TypeScript provides powerful utility types:

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

// Only pick certain fields
type PublicUser = Pick<User, 'id' | 'name'>;

// Make all fields optional
type PartialUser = Partial<User>;

// Make all fields required
type RequiredUser = Required<User>;