The **public‑array‑container‑by‑type‑implementation** package provides a single private helper function used inside subclasses of `PublicArrayContainer` that implement a `.byType()` method. It abstracts the logic for selecting items of a specific JavaScript type (number, string, object, etc.) by delegating to the subclass’s `byTest` routine, allowing developers building custom array‑container classes to reuse the type‑filtering code without rewriting it.