@flex-development/tutils/src/types/path-n.ts

TypeScript utilities

/**
 * @file Type Definitions - PathN
 * @module tutils/types/PathN
 */

import type Join from './join'
import type ObjectPlain from './object-plain'

/**
 * Constructs a union type of properties nested under `T[K]`.
 *
 * @see https://github.com/ghoullier/awesome-template-literal-types#dot-notation-string-type-safe
 *
 * @template T - Object type
 * @template K - Key containing nested properties
 */
type PathN<T extends ObjectPlain, K extends keyof T> = K extends string
  ? T[K] extends ObjectPlain
    ?
        | Join<K, Exclude<keyof T[K], keyof any[]> & string, '.'>
        | Join<K, PathN<T[K], Exclude<keyof T[K], keyof any[]>> & string, '.'>
    : never
  : never

export { type PathN as default }