Angular 17+: How to lazy-load 3rd party libraries that are only used by one standalone component

Angular 17+ brings a lot of exciting features to the table, but one of the most significant advantages is the ability to lazy-load 3rd party libraries that are only used by one standalone component. In this article, we’ll explore how to take advantage of this feature and improve the performance of your Angular application.

What is lazy-loading, and why is it important?

Lazy-loading is a technique where you load a script or a module only when it’s needed, rather than loading it initially. This approach can significantly improve the performance of your application by reducing the initial load time and minimizing the amount of code that needs to be loaded upfront.

In the context of Angular, lazy-loading is particularly important because it allows you to load 3rd party libraries only when they’re needed, rather than loading them globally. This can help reduce the overall size of your application and improve its performance.

Why lazy-load 3rd party libraries?

There are several reasons why you might want to lazy-load 3rd party libraries:

• Reduce initial load time**: By lazy-loading 3rd party libraries, you can reduce the initial load time of your application, making it faster and more responsive.
• Improve performance**: Lazy-loading 3rd party libraries can help improve the overall performance of your application by reducing the amount of code that needs to be loaded and executed.
• Minimize dependencies**: By lazy-loading 3rd party libraries, you can minimize the dependencies between different components and modules, making it easier to manage and maintain your application.

How to lazy-load 3rd party libraries in Angular 17+

Lazy-loading 3rd party libraries in Angular 17+ is relatively straightforward. Here’s a step-by-step guide to get you started:

Step 1: Create a standalone component

The first step is to create a standalone component that will use the 3rd party library. Let’s say we want to create a component that uses the Chart.js library to render charts.

< chart-component >
    < div >
        < canvas id="chart" ></canvas>
    </div>
</chart-component>

Step 2: Create a wrapper module for the 3rd party library

The next step is to create a wrapper module for the 3rd party library. This module will load the library and make it available to the component.

import { NgModule } from '@angular/core';
import * as Chart from 'chart.js';

@NgModule({
    providers: [
        {
            provide: 'Chart',
            useValue: Chart
        }
    ]
})
export class ChartModule { }

Step 3: Lazy-load the wrapper module

The next step is to lazy-load the wrapper module using the `import()` function.

import { Component } from '@angular/core';
import { import } from 'angular';

@Component({
    selector: 'chart-component',
    template: '<chart></chart>',
    standalone: true
})
export class ChartComponent {
    constructor(private readonly chartModule: import('chart/chart.module').then(m => m.ChartModule)) { }

    ngAfterViewInit(): void {
        this.chartModule.then(m => m.Chart).then(Chart => {
            const ctx = document.getElementById('chart');
            new Chart(ctx, {
                type: 'line',
                data: [...],
                options: {...}
            });
        });
    }
}

Step 4: Add the component to the router module

The final step is to add the component to the router module.

import { NgModule } from '@angular/core';
import { RouterModule, Routes } from '@angular/router';
import { ChartComponent } from './chart/chart.component';

const routes: Routes = [
    {
        path: 'charts',
        component: ChartComponent
    }
];

@NgModule({
    imports: [RouterModule.forRoot(routes)],
    exports: [RouterModule]
})
export class AppRoutingModule { }

That’s it! With these steps, you’ve successfully lazy-loaded the Chart.js library using a standalone component in Angular 17+.

Best practices for lazy-loading 3rd party libraries

While lazy-loading 3rd party libraries can be a powerful technique, it’s essential to follow best practices to ensure that your application remains maintainable and scalable:

1. Use a consistent naming convention**: Use a consistent naming convention for your wrapper modules and components to make it easier to identify and maintain them.
2. Keep wrapper modules small and focused**: Keep your wrapper modules small and focused on a specific 3rd party library to avoid bloating your application.
3. Use the `import()` function carefully**: Use the `import()` function carefully to ensure that you’re not loading unnecessary modules or libraries.
4. Test thoroughly**: Test your application thoroughly to ensure that the lazy-loaded 3rd party libraries are working as expected.

Conclusion

Lazy-loading 3rd party libraries in Angular 17+ is a powerful technique that can significantly improve the performance and maintainability of your application. By following the steps outlined in this article, you can easily lazy-load 3rd party libraries using standalone components and wrapper modules. Remember to follow best practices to ensure that your application remains scalable and maintainable.

Library	Wrapper Module	Component
Chart.js	ChartModule	ChartComponent

This article has provided a comprehensive guide to lazy-loading 3rd party libraries in Angular 17+. By implementing these techniques, you can take your application to the next level and provide a better user experience for your users.

Remember, lazy-loading 3rd party libraries is just one of the many techniques you can use to improve the performance of your Angular application. Experiment with different approaches and find what works best for your specific use case.

Here is the FAQ about lazy-loading 3rd party libraries in Angular 17+, written in a creative voice and tone:

Frequently Asked Questions

Get ready to optimize your Angular app with these frequently asked questions about lazy-loading 3rd party libraries!