vue-composition-api_skill

Overview

This skill teaches production-grade mastery of the Vue Composition API, covering composables, reactivity utilities, <script setup>, and provide/inject patterns. It focuses on building reusable, testable, and SSR-safe composables for modern Vue applications. Outcomes include practical composable architecture, advanced reactivity techniques, and patterns for sharing state across component trees.

How this skill works

The skill guides learners through progressive modules: Script Setup basics, deep reactivity utilities (ref, reactive, toRef, customRef, etc.), composable architecture, provide/inject patterns, and advanced composition patterns. Each module includes clear exercises, validation checkpoints, and testing templates to enforce single-responsibility composables, lifecycle management, and cleanup. Observability and retry logic are suggested for production readiness.

When to use it

• When converting Options API components to Composition API for better reusability
• When you need to extract shared logic into reusable composables
• When optimizing performance with shallowRef, customRef, or debounced inputs
• When sharing app-wide state or contexts using provide/inject (theme, auth, config)
• When designing composable libraries or SSR-safe async composables

Best practices

• Follow single-responsibility for composables: state, computed, methods, lifecycle, return a minimal public API
• Return refs or readonly refs instead of raw values to preserve reactivity
• Use toRef/toRefs when destructuring reactive objects to avoid lost reactivity
• Always register cleanup with onUnmounted for observers, timers, and subscriptions
• Write unit tests for composables using a simple template and validate initial state, actions, and reset behavior

Example use cases

• Create useFetch composable with loading, error, and refetch controls for data layers
• Build useStorage to sync reactive state with localStorage and handle serialization
• Compose useAuth with useFetch to implement authenticated data fetching and token refresh
• Implement a ThemeProvider via provide/inject to expose reactive theme and toggles across the app
• Design useDebounce and useIntersection composables for input control and lazy-loading UI