...It uses a realistic “bookshelf” domain where users can manage lists of books, track reading status, and record notes, which provides a concrete context for learning. The repository includes setup scripts and system requirements checks for Git, Node, and npm, plus Docker and Codespaces options for people who struggle with local environments. A guided workflow, driven by a node go script and INSTRUCTIONS.md, lets learners move between exercises and extra credit steps while the repository updates the working files for each stage. Extensive tests, using Jest in watch mode, help students verify their solutions and learn how to work with test-driven feedback.