Composition API

Organizing Logic with Composition API

The Composition API groups code by concern using imported functions instead of option buckets.

It scales better for large components and enables composable reuse.

import { ref, computed } from 'vue'
export function useCounter() {
  const count = ref(0)
  const doubled = computed(() => count.value * 2)
  return { count, doubled }
}

Reusable counter composable.

Benefits

better TypeScript, flexible reuse, clearer large files when structured

• Prefer Composition API + script setup.
• Use computed for derived UI.
• Keep side effects intentional.
• Practice in a small Vite app.

Composition API Cheatsheet

Quick reference for patterns covered in this lesson.

Structure Tip

Group by feature inside script setup with comment headers.

Common Mistakes

• Giant setup with no extraction.
• Returning unused refs everywhere.

Key Takeaways

• Composition API is important in Vue apps.
• Practice in SFCs.
• Prefer clear naming.
• Check Vue docs for details.