App function in Vue3: Create an instance object of Vue3

Vue is a popular JavaScript framework. Through Vue, you can realize component development and responsive data binding of applications. Vue 3 is the latest version of the Vue framework, which introduces many new features, one of which is the app function. This article will introduce in detail the app function of Vue3 and the process of creating a Vue3 instance object.

1. The app function in Vue3

The app function is a function in Vue3 that creates a Vue instance object. It can accept a root component as a parameter. In Vue2, we use new Vue to instantiate a Vue object, while in Vue3, we use the app function to instantiate the Vue object. The app function is indispensable when you want to create a Vue application.

2. Create an instance object of Vue3

Let’s take a look at how to create an instance object of Vue3 through the app function.

First, add a div element with the id app in the html file, which will serve as the root node of the Vue application:

<div id="app"></div>

In Vue3, you first need to create a Vue object instance through createApp , pass the component as a parameter in createApp, and then call the mount method to mount it on the root element.

const app = Vue.createApp({
  // 组件定义
})

app.mount('#app')

In the component definition, we can define the component's template, data, methods, etc. In the above code, we define an empty component, and then use the mount method of the app object to mount it on the div element with the id of app.

We can also pass multiple component parameters in createApp, as shown below:

const app = Vue.createApp({
  // 组件定义 1
},{
  // 组件定义 2
})

app.mount('#app')

In this way, we can create multiple components and combine them to implement complex application logic . In a component, we can use options such as template, data, and methods to define the component's template, data, methods, etc.

In Vue3, in addition to using the app function to create Vue object instances, we can also use plug-ins to extend the Vue3 framework to achieve more complex functions. Vue3 provides a new plug-in extension method, making the development and use of plug-ins more convenient.

In general, the app function in Vue3 is a very important part of the Vue framework. Through it, we can create an instance object of Vue and define various options of the component in it to implement the components of the application. construction.

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