Ionic angular Preload all module only on device

Question

How to use preload all strategy on device and nopreload on browser? we can load all module like this:

imports: [
CommonModule,
RouterModule.forRoot(appRoutes, { preloadingStrategy: PreloadAllModules }),
...
],

This will preload all module in any platform, But i want to prevent preload when running on browser. And it must only preload on device

Answer 1

It is possible with Ionic's Platform and Angular PreloadingStrategy. You need to have a custom preloading strategy. Here is a sample strategy doing what you want.

import { Injectable } from '@angular/core';
import { PreloadingStrategy, Route } from '@angular/router';
import { Observable, of } from 'rxjs';
import { Platform } from '@ionic/angular';

@Injectable({
    providedIn: 'root'
})
export class LocalOnlyPreloadingStrategy implements PreloadingStrategy {
    constructor(private platform: Platform) { }
    public preload(route: Route, fn: () => Observable<boolean>): Observable<boolean> {
        if (this.platform.is('hybrid')) {
            // Running on a device
            return fn();
        }
        // Not running on a device
        return of(false);
    }
}

You can import and use just like you are using PreloadAllModules in your code.

imports: [
CommonModule,
RouterModule.forRoot(appRoutes, { preloadingStrategy: LocalOnlyPreloadingStrategy }),
...
],
providers: [LocalOnlyPreloadingStrategy]

For more information;

• https://celilsemi.erkiner.com/blog/ionic-angular-preload-modules-only-on-device/
• https://ionicframework.com/docs/angular/platform
• https://angular.io/api/router/PreloadingStrategy