What are Components in Vue.js ? How to register a component inside other component

In Vue.js, components are reusable Vue instances with nearly all the functionality of a Vue instance. Components can leverage many features of Vue, such as templates, computed properties, and methods. In complex applications, components serve as fundamental building blocks for separating the application's interface and logic.

Key characteristics of components include:

• Reusability: By defining abstract components, we can reuse the same component across different projects or multiple times within the same project.
• Encapsulation: The internal implementation of a component is isolated, allowing changes to its internals without affecting other components.
• Composability: Components can be nested and combined with other components to build complex application interfaces.

How to Register a Component in Other Components?

In Vue, there are two ways to register components: global registration and local registration.

1. Global Registration:

Components registered globally can be used in any template of a new Vue root instance. Global registration is typically performed during application startup using the Vue.component method.

For example, define a global component named 'my-component':

javascript
Vue.component('my-component', {
  template: '<div>A custom component!</div>'
});

After registration, it can be used in any Vue instance's template:

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

javascript
new Vue({ el: '#app' });

2. Local Registration:

Unlike global registration, locally registered components are confined to a specific Vue instance or component context.

For example, consider a parent component where we want to use 'my-component':

javascript
import MyComponent from './MyComponent.vue';

export default {
  components: {
    'my-component': MyComponent
  }
}

This ensures 'my-component' can only be used within the parent component's template.

Example Illustration:

Suppose we are developing a blog system. We might have a BlogPost component that is locally registered in the homepage component to display the latest blog posts.

By using local registration, we maintain a clean global namespace while enhancing project maintainability.