ts-essentials

import { Prettify, DeepReadonly, StrictOmit, Paths, PathValue } from 'ts-essentials'; interface User { id: string; name: string; email?: string; address: { street: string; city: string; zip: number; coordinates?: [number, number]; }; preferences: { theme: 'dark' | 'light'; notifications: boolean; }; roles: ('admin' | 'editor' | 'viewer')[]; } // Prettify: Flattens and makes types more readable in IDE tooltips type PrettyUser = Prettify<User>; // DeepReadonly: Makes all properties and nested properties readonly type ImmutableUser = DeepReadonly<User>; // ImmutableUser.address.street = 'New Street'; // Type Error: Cannot assign to 'street' because it is a read-only property. // StrictOmit: Constructs a type by picking all properties from Type and then removing Keys. // It is a stricter version of TypeScript's built-in Omit. type UserWithoutSensitiveInfo = StrictOmit<User, 'email' | 'address.coordinates' | 'roles'>; const newUser: UserWithoutSensitiveInfo = { id: 'abc-123', name: 'Jane Doe', address: { street: 'Main St', city: 'Anytown', zip: 12345 }, preferences: { theme: 'dark', notifications: true } // email: 'jane@example.com' // Type Error: Object literal may only specify known properties }; // Paths: Generates a union of all possible string paths within an object type type UserPathExamples = Paths<User>; // UserPathExamples could include 'id' | 'address.city' | 'preferences.theme' | 'roles.0' // PathValue: Retrieves the type of the value at a specific path type AddressCityType = PathValue<User, 'address.city'>; // string type FirstRoleType = PathValue<User, 'roles.0'>; // 'admin' | 'editor' | 'viewer'