Service Providers

Understand the changes to defining service providers

For most Angular applications, services can be provided very simply, simply by including the class in the array of providers in your module. With NgRX Auto-Entity, due to its dynamic nature we must change how services for entities are provided a little bit.

Mapping Model to Service

Instead of registering the service itself directly, we must instead register the model class as the provider, and map it to an entity service via the useClass option. Like so:

src/app/app.module.ts

import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { NgrxAutoEntityModule } from '@briebug/ngrx-auto-entity';

import { AppComponent } from './app.component';

import { Customer } from 'models';
import { CustomerService } from 'services/customer.service';

@NgModule({
  declarations: [AppComponent],
  imports: [BrowserModule, NgrxAutoEntityModule],
  providers: [
    { provide: Customer, useClass: CustomerService }
  ],
  bootstrap: [AppComponent]
})
export class AppModule {}

When dispatching an action, the model class is specified as the first parameter, and as such the model class is the only thing NgRX Auto-Entity can use to look up the necessary service provider. By mapping the model class to the service class, you are leveraging a standard Angular paradigm to support dynamic service lookup at runtime.