TypeScript Best Practices for 2026

TypeScript has become the de facto standard for building robust JavaScript applications. 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
  }
}

This enables all strict type-checking options and helps catch potential bugs early.

Prefer Type Inference

Let TypeScript infer types when possible:

// Good
const message = "Hello, World!"

// Unnecessary
const message: string = "Hello, World!"

Use Discriminated Unions

Discriminated unions are powerful for modeling complex state:

type LoadingState =
  | { status: 'idle' }
  | { status: 'loading' }
  | { status: 'success'; data: string }
  | { status: 'error'; error: Error }

Avoid any

The any type defeats the purpose of TypeScript. Use unknown instead:

// Bad
function process(data: any) {
  return data.value
}

// Good
function process(data: unknown) {
  if (typeof data === 'object' && data !== null && 'value' in data) {
    return data.value
  }
}

Use Utility Types

TypeScript provides many useful utility types:

type User = {
  id: string
  name: string
  email: string
}

type PartialUser = Partial<User>
type ReadonlyUser = Readonly<User>
type UserWithoutEmail = Omit<User, 'email'>

Conclusion

Following these best practices will help you write more maintainable and type-safe TypeScript code. Keep learning and stay updated with the latest TypeScript features!