Quick Start

Getting started with NgRx Auto-Entity is easy!

If you are already familiar with NgRx, then adding Auto-Entity to your Angular application is very easy. There are four major steps required to add the module, create new entity state, and provide your entity services.

Step 1: Importing the Module

First things first, you must bring in the NgrxAutoEntityModule into your app module and call the forRoot() method to configure the library.

import { NgrxAutoEntityModule } from '@briebug/ngrx-auto-entity';
// ... other imports ...

@NgModule({
    imports: [
        BrowserModule,
        StoreModule.forRoot(appReducer, { metaReducers: appMetaReducers }),
        EffectsModule.forRoot([]),
        NgrxAutoEntityModule.forRoot() // Add this!
    ]
})
export class AppModule {}

Step 2: Creating your Model and Entity Service

Entity Models

Before you can actually create your state, you will need to create your entity models, as you would normally do. Auto-Entity requires two small changes to how you create models for NgRx.

models/customer.model.ts

import { Key } from '@briebug/ngrx-auto-entity';

export class Customer {
    @Key id: number;
    name: string;
    address: Address;
}

First, your models must be classes rather than interfaces (see advanced documentation for more info.) Second, your entity identity must be decorated with the @Key directive. For entities with composite keys, simply decorate each property that is part of the key.

Entity Services

You will also need to create an entity service to handle CRUD behavior for each entity. Entity services may be shared if your API uses a common pattern. Otherwise you may need to implement a service for each entity as you usually do with NgRx.

services/entity.service.ts

import { HttpClient } from '@angular/common/http';
import { Injectable } from '@angular/core';
import { Observable } from 'rxjs';
import { map } from 'rxjs/operators';

import { IAutoEntityService, IEntityInfo } from '@briebug/ngrx-auto-entity';
import { environment } from '../../environments/environment';

@Injectable()
export class EntityService implements IAutoEntityService<any> {
  constructor(private http: HttpClient) {
  }

  load(entityInfo: IEntityInfo, id: any): Observable<any> {
    return this.http.get<any>(
      `${environment.rootUrl}/${entityInfo.modelName}/${id}`
    );
  }

  loadAll(entityInfo: IEntityInfo): Observable<any[]> {
    return this.http.get<any[]>(
      `${environment.rootUrl}/${entityInfo.modelName}`
    );
  }

  create(entityInfo: IEntityInfo, entity: any): Observable<any> {
    return this.http.post<any>(
      `${environment.rootUrl}/${entityInfo.modelName}`,
      entity
    );
  }

  update(entityInfo: IEntityInfo, entity: any): Observable<any> {
    return this.http.patch<any>(
      `${environment.rootUrl}/${entityInfo.modelName}/${entity.id}`,
       entity
    );
  }

  delete(entityInfo: IEntityInfo, entity: any): Observable<any> {
    return this.http.delete<any>(
      `${environment.rootUrl}/${entityInfo.modelName}/${entity.id}`
    ).pipe(map(() => entity));
  }
}

In the example above we have a simple shared entity service that supports a basic REST API where each entity conforms to a simple pattern:

/<rootUrl>/<entityName>[/<key>]

Auto-Entity provides basic entity metadata, such as the model name, in the entityInfo parameter of each entity service method.

Step 3: Providing your Services

Once you have created an entity service or services, you will need to provide them in your app module. With Auto-Entity, services must be provided in a slightly different manner than normal, to ensure that Auto-Entity is able to find entity services dynamically.

app.module.ts

import { NgrxAutoEntityModule } from '@briebug/ngrx-auto-entity';
import { Customer, Order } from './models';
import { EntityService } from './services';
// ... other imports ...

@NgModule({
  imports: [
    BrowserModule,
    StoreModule.forRoot(...),
    EffectsModule.forRoot(...),
    NgrxAutoEntityModule.forRoot()
  ],
  // Add a provider for each model, mapping to the relevant entity service:
  providers: [
    { provide: Customer, useClass: EntityService },
    { provide: Order, useClass: EntityService }
  ]
})
export class AppModule {}

In our example here, we are sharing a single entity service, EntityService, for all entities. We must provide each model and useClass to specify the service class to use.

Step 4: Adding your States

Finally, now that you have your models and have provided your entity services, you need to build your state for each model. Add a new state file for each model following the pattern depicted here:

state/customer.state.ts

import { buildState, IEntityState } from '@briebug/ngrx-auto-entity';
import { Customer } from '../models'

export const { initialState, facade: CustomerFacadeBase } = buildState(Customer);

// A "stub" reducer is required to support AOT
export function customerReducer(state = initialState): IEntityState<Customer> {
  return state;
}

Finally, include your entity states in the AppState interface, and your stub reducers in the action reducer map:

state/app.state.ts

import { IEntityState } from '@briebug/ngrx-auto-entity';
import { Customer, Order } from 'models';
import { customerReducer } from './customer.state.ts'
import { orderReducer } from './order.state.ts'

export interface IAppState {
  // ... other states ...
  customer: IEntityState<Customer>;
  order: IEntityState<Order>;
}
export type AppState = IAppState;

export const appReducer: ActionReducerMap<AppState> = {
  // ... other reducers ...
  customer: customerReducer
  order: orderReducer
};

With that, you are ready to start using your automatic entity state! Continue on to the next section to learn how.