Difference between Options Api and Composition Api in Vue js

What is the Options API?

The Options API is Vue's original component organization pattern that most developers are familiar with. It structures component logic using options like data, methods, computed, and lifecycle hooks.

Vue.js Options API example

// Options API Example

<script>
export default {
  // Properties returned from data() become reactive state
  // and will be exposed on `this`.
  data() {
    return {
      count: 0
    }
  },

  // Methods are functions that mutate state and trigger updates.
  // They can be bound as event handlers in templates.
  methods: {
    increment() {
      this.count++
    }
  },

  // Lifecycle hooks are called at different stages
  // of a component's lifecycle.
  // This function will be called when the component is mounted.
  mounted() {
    console.log(`The initial count is ${this.count}.`)
  }
}
</script>

<template>
  <button @click="increment">Count is: {{ count }}</button>
</template>

Key Characteristics of Options API:

• Organization by option type: Related code is often split across different sections
• this context: Access properties and methods via this
• Beginner-friendly: Clear structure makes it easier to learn
• Implicit reactivity: Vue handles reactivity behind the scenes

What is the Composition API?

Introduced in Vue 3, the Composition API provides a more flexible way to organize component logic using imported functions rather than options.

Vue.js Composition API example:

// Composition API Example
<script setup>
import { ref, onMounted } from 'vue'

// reactive state
const count = ref(0)

// functions that mutate state and trigger updates
function increment() {
  count.value++
}

// lifecycle hooks
onMounted(() => {
  console.log(`The initial count is ${count.value}.`)
})
</script>

<template>
  <button @click="increment">Count is: {{ count }}</button>
</template>

Key Characteristics of Composition API:

• Organization by logical concern: Related code stays together
• Explicit imports: You import only what you need
• Better TypeScript support: Works naturally with TypeScript
• Reusability: Easier to extract and share logic between components
• More control over reactivity: Uses ref and reactive explicitly

Main Difference Between Options API and Composition API

(Vue 3 options API vs composition API):

Which API is better for Vue 3? When to Use Each API

• Choose Options API When:

1. You're new to Vue.js
2. Building simple to moderately complex components
3. Working on small projects where advanced state management isn't needed
4. Preferring a more declarative style of coding

• Choose Composition API When:

1. Building large, complex applications
2. Needing to share logic between multiple components
3. Using TypeScript for better type inference
4. Wanting more flexibility in organizing your code
5. Working with advanced reactivity patterns

Performance Considerations

Both APIs ultimately compile to similar code, so there's no significant performance difference at runtime. The Composition API might offer slight advantages in:

1. Better tree-shaking: Only imported functions are bundled
2. More efficient re-renders: Precise control over reactivity
3. Smaller bundles: When properly optimized

Can I use both APIs in one component?

Vue 3 fully supports both APIs, and you can even use them together in the same component:

export default {
 // Options API
 data() {
   return {
     optionsData: 'Hello'
   }
 },
 
 // Composition API
 setup() {
   const compositionData = ref('World')
   
   return {
     compositionData
   }
 }
}

However, for consistency, it's generally better to choose one approach per component.

Conclusion