LeafDataProptype

{
	readonly [K in DataKey<T>]: (
		T[K] extends Data
			? LeafDataProp<T[K]> //
			: readonly [null, T[K]]
	) extends infer E
		? E extends readonly [infer KK, infer VV]
			? readonly [KK extends string ? `${K}.${KK}` : K, VV]
			: never
		: never;
}[DataKey<T>]

Type
`DataKey`	Helper type to get the key for a data object prop.
`K`
`Data`	Data object — a plain object with string keys and unknown values.
`LeafDataProp`	Helper type to get the leaf props for a flattened data object with deep paths flattened into a.c.b format.
`E`
`KK`
`VV`

Helper type to get the leaf props for a flattened data object with deep paths flattened into a.c.b format.