TypeScript Best Practices for 2025

TypeScript has become an essential tool for modern web development. Here are some best practices to help you write better TypeScript code.

Use Strict Mode

Always enable strict mode in your tsconfig.json:


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

This catches potential errors at compile time rather than runtime.

Prefer Interfaces Over Type Aliases for Objects

When defining object shapes, prefer interfaces:


// Good
interface User {
  id: number;
  name: string;
  email: string;
}
 
// Less ideal for objects
type User = {
  id: number;
  name: string;
  email: string;
}

Interfaces can be extended and merged, making them more flexible for object definitions.

Use Utility Types

TypeScript provides powerful utility types that can save you time:


interface Todo {
  title: string;
  description: string;
  completed: boolean;
}
 
// Make all properties optional
type PartialTodo = Partial<Todo>;
 
// Make all properties required
type RequiredTodo = Required<Todo>;
 
// Pick specific properties
type TodoPreview = Pick<Todo, 'title' | 'completed'>;
 
// Omit specific properties
type TodoInfo = Omit<Todo, 'completed'>;

Avoid Using `any`

The any type defeats the purpose of TypeScript. Instead, use unknown when the type is truly unknown:


// Bad
function processValue(value: any) {
  return value.toString();
}
 
// Good
function processValue(value: unknown) {
  if (typeof value === 'string' || typeof value === 'number') {
    return value.toString();
  }
  throw new Error('Invalid value type');
}