Writing Clean TypeScript Code

TypeScript is powerful, but its power can lead to complexity. Here are battle-tested patterns for clean, maintainable TypeScript.

Type System Best Practices

Prefer Interfaces for Object Shapes

``typescript
// Good
interface User {
id: string;
name: string;
email: string;
}

// Avoid for complex objects
type User = { id: string; name: string; email: string; };
`

### Use Discriminated Unions

`typescript
type Result =
| { success: true; data: T }
| { success: false; error: string };
`

## Naming Conventions

- Interfaces: PascalCase (IUser or User)
- Types: PascalCase
- Enums: PascalCase with UPPER values
- Functions: camelCase
- Constants: UPPER_SNAKE_CASE

## Functional Patterns

Favor immutability and pure functions:

`typescript
// Good
const updateUser = (user: User, updates: Partial): User => ({
...user,
...updates,
});
``

## Error Handling

Use typed error handling with Result types or custom error classes.