TypeScript Best Practices for 2024

TypeScript continues to evolve, and with it, best practices for writing type-safe code. Here are the essential patterns you should know.

Strict Type Checking

Enable strict mode in your tsconfig.json:

{
  "compilerOptions": {
    "strict": true,
    "noImplicitAny": true,
    "strictNullChecks": true
  }
}

Type Inference

Let TypeScript infer types when possible:

// Good - TypeScript infers the type
const users = ['Alice', 'Bob', 'Charlie'];

// Only add explicit types when necessary
const userCount: number = users.length;

Discriminated Unions

Use discriminated unions for type-safe state management:

type LoadingState = { status: 'loading' };
type SuccessState = { status: 'success'; data: string };
type ErrorState = { status: 'error'; error: Error };

type State = LoadingState | SuccessState | ErrorState;

function handleState(state: State) {
  switch (state.status) {
    case 'loading':
      return 'Loading...';
    case 'success':
      return state.data;
    case 'error':
      return state.error.message;
  }
}

Utility Types

Leverage built-in utility types:

• `Partial<T>` - Make all properties optional
• `Required<T>` - Make all properties required
• `Pick<T, K>` - Select specific properties
• `Omit<T, K>` - Exclude specific properties

Best Practices

1. **Avoid any** - Use unknown or proper types instead 2. **Use const assertions** - For literal types 3. **Prefer interfaces for objects** - Use types for unions/intersections 4. **Document complex types** - Add JSDoc comments

TypeScript is a powerful tool for building robust applications. Follow these practices to maximize its benefits.