More Utility Types

type Shelf = Record<string, number>
type LockedBook = Readonly<{ title: string; pages: number }>
type BookPreview = Omit<{ id: string; title: string; summary: string }, 'id'>
type FullBook = Required<{ title?: string; author?: string }>

type Status = 'draft' | 'published' | null
type PublishedOnly = Exclude<Status, 'draft' | null>

Object Utilities

• Record<K, V> - Create object with keys K and values V
• Readonly<T> - Make all properties readonly
• Omit<T, K> - Remove properties K from T
• Required<T> - Make all properties required

Union Utilities

• Exclude<T, U> - Remove types assignable to U from T
• Extract<T, U> - Keep only types assignable to U in T
• NonNullable<T> - Remove null and undefined from T

1. Use Record to create a config type
2. Use Readonly to make a user immutable
3. Use Omit to create a user type without id
4. Use Required to make optional properties required
5. Use Exclude, Extract, and NonNullable on union types