Vue 3 Component Global and Local Registration

In Vue 3, component registration is divided into two methods: global registration and local registration. Both can be used to register components in an application so that they are available for use within templates.
Global registration makes a component globally accessible, allowing it to be used anywhere in the application without explicit imports. This approach is suitable for components that are widely used throughout the entire application.

Below is an example demonstrating how to register a component globally in Vue 3:

// In main.js or any entry file of your application
import { createApp } from 'vue';
import App from './App.vue';
import MyComponent from './components/MyComponent.vue';

const app = createApp(App);
app.component('my-component', MyComponent);
app.mount('#app');

In the code above, we use the app.component method to register the MyComponent as a global component. The first argument is the name of the component (used in templates), and the second argument is the definition of the component itself.

Once a component is globally registered, you can use it within any template across your application, as shown below:

<template>
  <div id="app">
    <my-component></my-component>
  </div>
</template>

Local Registration

Local registration registers a component within the context of a specific parent component or module. It can only be used inside that parent component or module. This approach is suitable for components used in limited scopes, helps avoid global naming conflicts, and improves encapsulation.

Below is an example demonstrating how to register a component locally in Vue 3:

// In the parent component or module
import MyComponent from './MyComponent.vue';

export default {
  // ...
  components: {
    'my-component': MyComponent,
  },
  // ...
}

In the code above, we register the MyComponent as a local component within the components option of the parent component or module. The property name 'my-component' is the name used for this component in templates within that specific parent component or module.

Once a component is locally registered, it can be used only within its corresponding parent component's or module's template, as shown below:

<template>
  <div>
    <my-component></my-component>
  </div>
</template>

Through local registration, the component remains restricted to use within the scope of the parent component or module, thereby offering better encapsulation and isolation.