Why TypeScript?

TypeScript adds type safety to JavaScript, catching errors at compile time rather than runtime. But types alone don’t guarantee clean code.

Use Strict Mode

Always enable strict mode in your tsconfig.json:

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

Prefer Interfaces Over Type Aliases for Objects

// ✅ Prefer interfaces for object shapes
interface User {
  id: string;
  name: string;
  email: string;
}

// ✅ Use type aliases for unions, intersections, mapped types
type Status = "active" | "inactive" | "pending";
type UserWithRole = User & { role: string };

Avoid any Like the Plague

// ❌ Don't do this
function processData(data: any) {
  return data.name;
}

// ✅ Do this instead
function processData(data: { name: string }) {
  return data.name;
}

// ✅ Or use generics
function processData<T extends { name: string }>(data: T) {
  return data.name;
}

Use Discriminated Unions

type Result<T> =
  | { success: true; data: T }
  | { success: false; error: string };

function handleResult(result: Result<User>) {
  if (result.success) {
    console.log(result.data.name); // TypeScript knows data exists
  } else {
    console.error(result.error);   // TypeScript knows error exists
  }
}

Utility Types Are Your Friend

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

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

// Pick specific properties
type UserName = Pick<User, "name" | "email">;

// Omit specific properties
type UserWithoutId = Omit<User, "id">;

Conclusion

TypeScript is most powerful when you embrace its type system fully. Invest time in learning advanced patterns — your future self will thank you.