Import Svelte component globally

2 min read 06-10-2024

Making Svelte Components Global: Simplifying Your Development

Svelte's component-based architecture encourages modularity and reusability. But sometimes, you need to use a component across your entire application. Instead of importing it individually into every file, wouldn't it be great to make it available globally? This article explores how to achieve just that, streamlining your workflow and improving code maintainability.

The Problem: Repeated Imports

Imagine having a simple "Notification" component that you want to display throughout your Svelte application. The traditional approach would involve importing it into every file where it's needed:

<!-- App.svelte -->
<script>
  import Notification from './Notification.svelte';
</script>

<!-- SomeComponent.svelte -->
<script>
  import Notification from './Notification.svelte';
</script>

This gets tedious quickly, especially with a growing project. Every time you add a new component or change the location of your Notification.svelte file, you need to update every import statement.

The Solution: Global Registration

Svelte doesn't have built-in global component registration. But we can leverage the power of Svelte's onMount lifecycle method and a simple workaround to achieve a similar effect. Here's how:

Create a global.js file:

// global.js
import Notification from './Notification.svelte';

export default {
  components: {
    Notification,
  },
};

Register the components globally:

<!-- App.svelte -->
<script>
  import global from './global.js';

  onMount(() => {
    Object.entries(global.components).forEach(([name, component]) => {
      customElements.define(name, component);
    });
  });
</script>

Use the component directly:

<!-- AnyComponent.svelte -->
<Notification message="This is a global notification!" />

Explanation:

In global.js, we import the Notification component and store it in a components object.
In App.svelte, we use onMount to register each component defined in global.js as a custom element. This makes the component available throughout the application.
Now, in any Svelte component, we can directly use <Notification> without needing an import.

Advantages of Global Components

Reduced code repetition: No more importing the same component everywhere.
Easier maintenance: When you change a global component, the changes are automatically reflected across your application.
Improved code organization: Keeps all global components in a single, dedicated file.

Considerations and Best Practices

Namespace your global components: For large projects, consider adding a namespace to your global components to prevent naming conflicts.
Use with caution: Don't overuse global components. For specific components, consider using local imports for better modularity.
Global state management: For managing global state across your application, explore solutions like Svelte stores.

Conclusion

Making components globally available simplifies Svelte development by reducing redundancy and enhancing code maintainability. By utilizing a simple approach with onMount and custom elements, you can enjoy the benefits of global components while maintaining a clear and organized codebase.