The Ultimate Guide to TypeScript Best Practices in 2024

TypeScript has become the standard for building robust JavaScript applications. Let's explore the best practices that will elevate your TypeScript code.

1. Use Strict Mode

Always enable strict mode in your tsconfig.json:

{
  "compilerOptions": {
    "strict": true,
    "noUncheckedIndexedAccess": true,
    "noImplicitOverride": true
  }
}

2. Avoid 'any' Type

The any type defeats the purpose of TypeScript. Use unknown for truly dynamic types:

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

// Good
function processData(data: unknown) {
  if (typeof data === 'object' && data !== null && 'value' in data) {
    return data.value
  }
  throw new Error('Invalid data')
}

3. Leverage Type Inference

Let TypeScript infer types when possible:

// Redundant
const name: string = "John"

// Better
const name = "John"

4. Use Discriminated Unions

Create type-safe state machines with discriminated unions:

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

5. Prefer Interfaces for Object Types

Use interfaces for object shapes and types for unions:

interface User {
  id: string
  name: string
  email: string
}

type Status = 'active' | 'inactive' | 'pending'

Pro tip: Always prefer type safety over convenience. Your future self will thank you!

Conclusion

These best practices will help you write more maintainable and type-safe TypeScript code. Happy coding!

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