FlattenObjectKeys

Build a union of dot-separated leaf paths for a nested object, with an optional prefix.

Similar to DeepKeyOf but only yields leaf paths (skips intermediate object keys), and accepts a Prefix parameter for namespacing.

Usage

import type { FlattenObjectKeys } from '@maz-ui/utils'

interface Config {
  app: {
    name: string
    version: number
  }
  debug: boolean
}

type Leaves = FlattenObjectKeys<Config>
// → 'app.name' | 'app.version' | 'debug'

type Namespaced = FlattenObjectKeys<Config, 'config.'>
// → 'config.app.name' | 'config.app.version' | 'config.debug'

API

type FlattenObjectKeys<T extends Record<string, any>, Prefix extends string = ''> = {
  [K in keyof T]: T[K] extends Record<string, any>
    ? FlattenObjectKeys<T[K], `${Prefix}${K extends string ? K : ''}.`>
    : `${Prefix}${K extends string ? K : ''}`
}[keyof T]

Notes

• Unlike DeepKeyOf, intermediate object keys (e.g. 'app' in the example) are not included — only the paths that resolve to non-object leaves.