Mastering Vue.js 3 Composition API

The Composition API is Vue 3's answer to complex component logic organization. It provides a more flexible and powerful way to build components.

Why Composition API?

The Composition API solves several limitations of the Options API:

• Better logic reuse between components
• More flexible code organization
• Better TypeScript integration
• Improved tree-shaking capabilities

Basic Setup Function

import { ref, computed, onMounted } from "vue";

export default {
  setup() {
    const count = ref(0);
    const doubleCount = computed(() => count.value * 2);
    
    const increment = () => {
      count.value++;
    };
    
    onMounted(() => {
      console.log("Component mounted!");
    });
    
    return {
      count,
      doubleCount,
      increment
    };
  }
};

Composables for Logic Reuse

Create reusable logic with composables:

// useCounter.js
import { ref } from "vue";

export function useCounter(initialValue = 0) {
  const count = ref(initialValue);
  
  const increment = () => count.value++;
  const decrement = () => count.value--;
  const reset = () => count.value = initialValue;
  
  return {
    count,
    increment,
    decrement,
    reset
  };
}

Advanced Patterns

Combine multiple composables for complex functionality:

export default {
  setup() {
    const { count, increment } = useCounter();
    const { isLoading, error, fetchData } = useApi();
    const { user, login, logout } = useAuth();
    
    return {
      count,
      increment,
      isLoading,
      error,
      fetchData,
      user,
      login,
      logout
    };
  }
};

"The Composition API doesn't replace the Options API - it's an additional way to compose component logic."

Start incorporating the Composition API into your Vue.js projects for better code organization and reusability.