Type Alias CollectionAtPath<TCollections, TPath>

CollectionAtPath: TPath extends `${infer THead}.${infer TRest}`
    ? THead extends keyof TCollections & string
        ? CollectionAtPath<TCollections[THead]["children"], TRest>
        : never
    : TPath extends keyof TCollections & string ? TCollections[TPath] : never

Type Parameters

TCollections extends CollectionDefinitions
TPath extends string