Which of the following best describes the purpose of frontend modules in Liferay?

The purpose of frontend modules in Liferay is to encapsulate both functionality and visual aspects for reuse. Frontend modules are designed to provide a cohesive package that includes not just the visual presentation of a component, such as styles and layouts, but also the underlying JavaScript functionality that enables interactive features. This modular approach allows developers to create reusable components that can be easily integrated into various parts of a Liferay application, promoting consistency and reducing duplication of effort.

This aspect of encapsulation is particularly beneficial in a collaborative development environment, where different teams may work on different components. By structuring frontend code into modules, developers can ensure that changes in one area do not inadvertently impact others, thereby supporting maintainability and scalability in the overall application architecture.

In contrast to other options, frontend modules are not solely for testing or backend services. While testing is a vital part of the development process, it is not the primary purpose of frontend modules. Similarly, backend services are managed through different structures and are not the focus of frontend module design. Maintenance tools for the codebase also fall outside the scope of what frontend modules are intended for, as these typically relate to aspects of code quality and management rather than the direct functionality and user interface components that frontend modules provide.