Vue 2 vs. Vue 3: Exploring the Evolution of Vue.js
Tags: technology, vue, softwaredevelopment, webdev
Published: 2024-01-11 04:25:35

In the dynamic landscape of web development, Vue.js has emerged as a powerful and versatile JavaScript framework, continuously evolving to meet the demands of modern applications. In this comprehensive blog post, we delve into the evolutionary journey of Vue.js, comparing Vue 2 and Vue 3 to help you navigate the transition and harness the full potential of this progressive framework. Join us as we explore the key enhancements, performance optimizations, and new features that Vue 3 brings to the table, providing valuable insights for developers looking to stay ahead in the ever-changing world of front-end development. Whether you’re a seasoned Vue.js enthusiast or just starting your journey, this guide aims to be your go-to resource for understanding the differences, advantages, and considerations when choosing between Vue 2 and Vue 3. Let’s embark on this insightful journey together and unlock the next level of Vue.js proficiency


## Virtual DOM

The foundation of Vue.js lies in the Virtual DOM (Document Object Model) technology. In Vue 2, the Virtual DOM is seamlessly integrated into Vue.js’s event loop. However, in Vue 3, the Virtual DOM has been redesigned and made more efficient. In Vue 3, the Virtual DOM is processed faster and uses less memory. This significantly enhances performance and application response times.

## Composition API

Vue 3 introduced the Composition API, one of its most notable features. The Composition API differs from the Options API in Vue 2 and makes your code more organized, maintainable, and reusable. In Vue 2, components are defined using options like data, methods, computed, and watch. In Vue 3, your code can be organized more functionally. The Composition API allows you to create smaller, more reusable, and customizable functions.

## TypeScript Integration

Vue.js is a popular choice for projects using static type checking tools like TypeScript. In Vue 2, TypeScript integration was possible, but developers might have encountered some difficulties and issues. Vue 3 significantly improved TypeScript integration. When using TypeScript with Vue 3, you get better static type control and a smoother TypeScript experience.

## Bundle Size

Bundle size is a crucial factor in large front-end projects. In Vue 2, various optimization techniques and plugins might be needed to reduce bundle size. However, in Vue 3, improvements such as an optimized matching algorithm and source code compression have significantly reduced bundle sizes. This results in smaller bundle sizes, faster loading times, and improved performance.

## Compatibility
Vue 3 might pose compatibility issues for developers transitioning from Vue 2 projects. Vue 3 may drop some APIs or components, and rename or alter others. Therefore, if you want to upgrade an existing Vue 2 project to Vue 3, you may encounter some compatibility issues. There is a detailed migration guide for Vue 3, and referring to this guide can guide the transition process.

## Creating App

Firstly, looking at the way to create an app, you will see the difference in syntax. Not only syntax but also essence is changed.

### Vue 2

```
import Vue from 'vue'
import App from './App.vue'

Vue.config.productionTip = false

new Vue({
  render: h => h(App),
}).$mount('#app')
```

### Vue 3

```
import { createApp } from 'vue'
import App from './App.vue'
import './index.css'

createApp(App).mount('#app')
```

### Reason for change

Global configurations make issues during testing in unit tests because test cases can affect each other by global configuration. All of those effects are pollution.
Vue 3 provides different global configurations but it makes it difficult to share a copy of configuration to multiple apps.

### Vue 2

```
// this mixin affects both below instances
Vue.mixin({ /* ... */ })

const app1 = new Vue({ el: '#app-1' })
const app2 = new Vue({ el: '#app-2' })
```

### Vue 3

```
const app = createApp(App)
// This configuration effect only 1 instance
app.mixin(/* ... */)
app.mount('#app')
```

### To access more content, please follow this link.

#### [Emperor Brains](https://medium.com/@emperorbrains/vue-2-vs-vue-3-exploring-the-evolution-of-vue-js-03dab173e8a3)