Instructions and covered skills
Read each prompt carefully before selecting a response. Focus on the behavior Vue provides rather than assumptions from other frameworks. Review code snippets for ref unwrapping, lifecycle context, and shared-state implications. Choose the response that best fits the stated requirement. Keep your work independent and avoid external references. Turn off notifications and stay focused until you have reviewed every response.
Key Areas
This test examines the design and use of Vue Composition API composables. Candidates work with ref, reactive, computed, readonly, and toRefs to create APIs that preserve Vue reactivity while remaining clear to component authors. It also covers the difference between state created during each composable call and state intentionally created at module scope for sharing across component instances.
Questions address lifecycle-aware logic, including registering cleanup through Vue lifecycle hooks and ensuring browser listeners, timers, subscriptions, and observers are released when a component is removed. Candidates should recognize that lifecycle hooks require an active component instance and should know when a composable is appropriate for encapsulating side effects.
The assessment also covers dependency injection with provide and inject. This includes using injection keys, configuring fallback values, supplying mutable or readonly dependencies, and enabling replacement dependencies for tests or feature-specific component trees. Attention is given to dependency ownership so that consumers can use an injected service without unexpectedly controlling its internal state.
Recommended Preparation
Review Vue's Composition API documentation and build small composables for a timer, network-status monitor, or data-fetching workflow. Practice returning refs, methods, and readonly state with intentional public interfaces. Compare local state created inside a composable with shared state declared outside it, and identify the consequences for multiple component instances and server-rendered applications.
Practice providing a service from an ancestor component and injecting it in descendants with a symbol key. Try supplying a fallback implementation and replacing a provided service in a test harness. Finally, inspect composables for cleanup responsibilities, caller-owned inputs, and places where destructuring could disconnect a reactive property from Vue's tracking system.