Vue.js 3.0 Tutorial

Vue.js 3.0 Component Advanced

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Vue 3.0 Style Guide

Vue 3.0 Application API

Vue 3.0 introduces the createApp function, a new way to create a Vue application. This replaces the previous new Vue() syntax used in Vue 2.x.

The new API provides a more straightforward way to create and configure a Vue application. Here's how you would create a basic Vue application with Vue 3.0:

import { createApp } from 'vue'
import App from './App.vue'

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

In the above code, we import createApp from vue and use it to create a new Vue application. We then mount the application to an element with the id app.

Let's build on this with a more comprehensive example:

import { createApp } from 'vue'
import App from './App.vue'
import MyComponent from './MyComponent.vue'

const app = createApp(App)

app.component('my-component', MyComponent)

app.mount('#app')

In this example, we're using the component method to globally register a component, MyComponent. This component can now be used anywhere in our App.

We can also use the directive, mixin, and use methods to globally register directives, mixins, and plugins:

import { createApp } from 'vue'
import App from './App.vue'
import MyDirective from './MyDirective.vue'
import MyMixin from './MyMixin'
import MyPlugin from './MyPlugin'

const app = createApp(App)

app.component('my-component', MyComponent)
app.directive('my-directive', MyDirective)
app.mixin(MyMixin)
app.use(MyPlugin)

app.mount('#app')

In Vue 3.0, each call to createApp will create a new application instance, isolated from others. As a result, global configurations (like component registration via app.component, app.directive, etc.) do not cross-contaminate between multiple apps.

Vue 3.0 Application Lifecycle Hooks:

Description: Lifecycle hooks allow you to execute code at different stages of a component's life cycle.

Code:

<script>
  export default {
    beforeCreate() {
      console.log('Before Create Hook');
    },
    created() {
      console.log('Created Hook');
    },
    mounted() {
      console.log('Mounted Hook');
    },
    // ... other hooks
  };
</script>

Vue 3.0 configure Method in Application API:

Description: The configure method is used to modify global configurations of Vue.

Code:

import { createApp } from 'vue';

const app = createApp(App);

app.configure('production', () => {
  // configure for production
});

app.mount('#app');

Vue 3.0 Handling Global Configuration in createApp:

Description: Use the config method in createApp to set global configurations.

Code:

import { createApp } from 'vue';

const app = createApp(App);

app.config.productionTip = false; // Disable production tip

app.mount('#app');

Vue 3.0 Creating a Vue Instance with createApp:
- Description: Use createApp to create a Vue instance and mount it to an element.
- Code:
```
import { createApp } from 'vue';
import App from './App.vue';

const app = createApp(App);

app.mount('#app');
```

Vue 3.0 mount and unmount Methods in Application API:

Description: mount is used to mount the app to a specified element, and unmount is used to unmount the app.

Code:

import { createApp } from 'vue';
import App from './App.vue';

const app = createApp(App);

const mountedApp = app.mount('#app');

// Later
mountedApp.unmount();

Vue 3.0 globalProperties in Application API:

Description: globalProperties allows you to add properties/methods globally accessible in components.

Code:

import { createApp } from 'vue';
import App from './App.vue';

const app = createApp(App);

app.config.globalProperties.$myGlobalMethod = () => {
  console.log('Global Method');
};

app.mount('#app');

Vue 3.0 Accessing App Context in Components:

Description: Use the app context to access global properties or methods in components.

Code:

<script>
  export default {
    mounted() {
      this.$appContext.config.globalProperties.$myGlobalMethod();
    },
  };
</script>