Foundation for all PrimeReact components. Provides `extend()` to define default props, CSS classes, and inline styles, along with `getProps()`, `setMetaData()`, and `useHandleStyle()` for consistent prop merging and style injection. This pattern is reusable in any component library that needs a standardized way to handle default props, theming, and pass-through customization.

A custom React hook that manages overlay positioning and event listeners (scroll, resize, click outside) for floating panels. It encapsulates the logic for binding/unbinding events and handling overlay visibility. This hook is self-contained and can be extracted for use in any project requiring overlay management.

A utility function that deeply merges component props with pass-through options, supporting style merging, function chaining, and custom class merge strategies (e.g., Tailwind). It is used across all components to combine default props, user props, and global pass-through configurations. This is a reusable pattern for any React library needing flexible prop customization.

Core implementation of the pass-through (pt) system that enables unstyled mode and Tailwind integration. It provides `usePassThrough` and related utilities to merge user-defined attributes into component DOM elements. This pattern is reusable for any UI library that wants to offer a customizable, unstyled mode without sacrificing component logic.

Manages internationalization for component strings (e.g., 'choose', 'noFilter', 'emptyMessage'). Provides `addLocale`, `locale`, `updateLocaleOption`, and `localeOption` functions. This is a self-contained module that can be reused in any React application needing a simple, global locale system.