Tell me, what is Feature-Sliced Design (FSD)? Share your experience with FSD.

Feature-Sliced Design (FSD) is a methodology for organizing frontend code, focused on dividing the project into functional slices (features). The main idea is to structure the application so that each feature is as isolated and self-contained as possible, which facilitates maintenance and scaling.

In FSD, the project is divided into levels and layers, for example:

• App — the root level of the application.
• Pages — pages of the application.
• Features — individual functional capabilities.
• Entities — business entities.
• Shared — common utilities and components.

Each layer is responsible for its area, dependencies only go from top to bottom, preventing cyclic dependencies.

In my experience, implementing FSD has helped to:

• Clearly divide responsibilities among teams.
• Simplify navigation through the code.
• Improve component reusability.

For example, when developing a large SPA, we highlighted key features (authorization, user profile, product catalog) into separate modules with their own state managers and UI components, which significantly accelerated development and testing.