voiskibrasil / ngx-lazy-el

Lazy Loading Angular Components made easy powered by Angular Elements

ngx-lazy-el

Easy lazy loading components 💪 by Angular Elements.

How to use it

Also check out my talks about using this library

• ngRome 2019 - Lazy Loading on Steroids (with Angular Elements)
• JSBE.io - Lazy Loading on Steroids with NG Elements

Install Angular Elements on your project

This library depends on Angular Elements. You can install that via

$ ng add @angular/elements

Install ngx-lazy-el

Install the library from npm.

$ npm install @juristr/ngx-lazy-el

or

$ yarn add @juristr/ngx-lazy-el

Lazy load a component

1) Configure the Module containing the lazy loaded component

First of all, expose the Angular Component that should be loaded via a customElementComponent property.

...
@NgModule({
  declarations: [HelloWorldComponent],
  ...
  exports: [HelloWorldComponent]
})
export class HelloWorldModule {
  customElementComponent: Type<any> = HelloWorldComponent;
}

2) Define the lazy component map in your AppModule

Just like with the Angular Router, define the map of component selector and lazy module.

// app.module.ts
...
const lazyConfig = [
  {
    selector: 'app-hello-world',
    loadChildren: () =>
      import('./hello-world/hello-world.module').then(m => m.HelloWorldModule)
  }
];

@NgModule({
  ...
  imports: [
    ...
    NgxLazyElModule.forRoot(lazyConfig),
  ],
  providers: [],
  bootstrap: [AppComponent]
})
export class AppModule {}

3) Use the lazy loaded Component

To use the lazy loaded component in another module, first of all register the CUSTOM_ELEMENT_SCHEMA.

import { ..., CUSTOM_ELEMENTS_SCHEMA } from '@angular/core';

@NgModule({
  schemas: [CUSTOM_ELEMENTS_SCHEMA],
  imports: [NgxLazyElModule]
  ...
})
export class SomeModule {}

That is needed because otherwise Angular won't recognize the tag as it is no more an Angular Component, but Custom Element. Also note that I import the NgxLazyElModule if you haven't already. Otherwise the *ngxLazyEl directive won't work.

Now you can just use the Custom Element by applying the *ngxLazyEl directive.

<app-hello-world *ngxLazyEl [person]="person"></app-hello-world>

If it is behind a *ngIf or other non-visible component, the app-hello-world will be lazy loaded on the fly.

Questions?

Open an issue or ping me on Twitter.