add feature to choose the property name of the primary key of collection

src/app/hero-in-mem-data-override-id.service.ts

@@ -0,0 +1,73 @@
+/**
+ * This is an example of a Hero-oriented InMemoryDbService.
+ *
+ * For demonstration purposes, it can return the database
+ * synchronously as an object (default),
+ * as an observable, or as a promise.
+ *
+ * Add the following line to `AppModule.imports`
+ *   InMemoryWebApiModule.forRoot(HeroInMemDataService) // or HeroInMemDataOverrideService
+ */
+import { Injectable } from '@angular/core';
+import { InMemoryDbService, RequestInfo } from '../in-mem/interfaces';
+
+// tslint:disable:no-unused-variable
+import { Observable } from 'rxjs/Observable';
+import { of } from 'rxjs/observable/of';
+import 'rxjs/add/operator/delay';
+// tslint:enable:no-unused-variable
+
+@Injectable()
+export class HeroInMemDataOverrideIdService implements InMemoryDbService {
+  defineId(collectionName: string) {
+    return 'uuid';
+  }
+  createDb(reqInfo?: RequestInfo) {
+
+    const heroes = [
+      { uuid: '00000000-0000-0000-0000-000000000001', name: 'Windstorm' },
+      { uuid: '00000000-0000-0000-0000-000000000002', name: 'Bombasto' },
+      { uuid: '00000000-0000-0000-0000-000000000003', name: 'Magneta' },
+      { uuid: '00000000-0000-0000-0000-000000000004', name: 'Tornado' }
+    ];
+
+    const nobodies: any[] = [];
+
+    // entities with string ids that look like numbers
+    const stringers = [
+      { uuid: '00000000-0000-0000-0000-000000000010', name: 'Bob String' },
+      { uuid: '00000000-0000-0000-0000-000000000020', name: 'Jill String' }
+    ];
+
+    // default returnType
+    let returnType = 'object';
+    // let returnType  = 'observable';
+    // let returnType  = 'promise';
+
+    // demonstrate POST commands/resetDb
+    // this example clears the collections if the request body tells it to do so
+    if (reqInfo) {
+      const body = reqInfo.utils.getJsonBody(reqInfo.req) || {};
+      if (body.clear === true) {
+        heroes.length = 0;
+        nobodies.length = 0;
+        stringers.length = 0;
+      }
+
+      // 'returnType` can be 'object' | 'observable' | 'promise'
+      returnType = body.returnType || 'object';
+    }
+    const db = { heroes, nobodies, stringers };
+
+    switch (returnType) {
+      case ('observable'):
+        return of(db).delay(10);
+      case ('promise'):
+        return new Promise(resolve => {
+          setTimeout(() => resolve(db), 10);
+        });
+      default:
+        return db;
+    }
+  }
+}

src/in-mem/backend.service.ts

@@ -28,6 +28,10 @@ import {
   UriInfo
 } from './interfaces';
 
+export interface IDictionary {
+  [index: string]: string;
+}
+
 /**
  * Base class for in-memory web api back-ends
  * Simulate the behavior of a RESTy web api
@@ -36,6 +40,7 @@ import {
  * http://www.restapitutorial.com/lessons/httpmethods.html
  */
 export abstract class BackendService {
+  protected fieldIds = {} as IDictionary;
   protected config: InMemoryBackendConfigArgs = new InMemoryBackendConfig();
   protected db: Object;
   protected dbReadySubject: BehaviorSubject<boolean>;
@@ -381,7 +386,48 @@ export abstract class BackendService {
    * @param id
    */
   protected findById<T extends { id: any }>(collection: T[], id: any): T {
-    return collection.find((item: T) => item.id === id);
+    return collection.find((item: T) => this.getItemId(item) === id);
+  }
+
+  /**
+   * define for your in-mem database what is the name of your id field
+   * return the name of the id field
+   */
+  protected defineId(collectionName = 'default_id'): string {
+    const defineId = this.bind('defineId');
+    if (defineId) {
+      const id = defineId(collectionName);
+      if ((id !== undefined) && id !== '') { return id; }
+    }
+    return 'id';
+  }
+
+  /**
+   * return the key (by id property name) of item for a collection name 
+   * @param item 
+   * @param collectionName 
+   */
+  protected getItemId<T extends { id: any }>(item: T, collectionName = 'default_id'): any {
+    return item[this.fieldIds[collectionName]];
+  }
+
+  /**
+   * set the key by property name of a item for a collection
+   * @param item 
+   * @param id 
+   * @param collectionName 
+   */
+  protected setItemId<T extends { id: any }>(item: T, id: any, collectionName = 'default_id'): any {
+    return item[this.fieldIds[collectionName]] = id;
+  }
+
+  /**
+   * set the property name of the key of a collection
+   * @param id 
+   * @param collectionName 
+   */
+  protected setFieldId(id: any, collectionName = 'default_id') {
+    this.fieldIds[collectionName] = this.defineId(collectionName);
   }
 
   /**
@@ -414,7 +460,7 @@ export abstract class BackendService {
 
     let maxId = 0;
     collection.reduce((prev: any, item: any) => {
-      maxId = Math.max(maxId, typeof item.id === 'number' ? item.id : maxId);
+      maxId = Math.max(maxId, typeof this.getItemId(item) === 'number' ? this.getItemId(item) : maxId);
     }, undefined);
     return maxId + 1;
   }
@@ -493,7 +539,7 @@ export abstract class BackendService {
   protected abstract getRequestMethod(req: any): string;
 
   protected indexOf(collection: any[], id: number) {
-    return collection.findIndex((item: any) => item.id === id);
+    return collection.findIndex((item: any) => this.getItemId(item) === id);
   }
 
   /** Parse the id as a number. Return original value if not a number. */
@@ -588,9 +634,9 @@ export abstract class BackendService {
     const item = this.getJsonBody(req);
 
     // tslint:disable-next-line:triple-equals
-    if (item.id == undefined) {
+    if (this.getItemId(item) == undefined) {
       try {
-        item.id = id || this.genId(collection, collectionName);
+        this.setItemId(item, id || this.genId(collection, collectionName));
       } catch (err) {
         const emsg: string = err.message || '';
         if (/id type is non-numeric/.test(emsg)) {
@@ -603,10 +649,10 @@ export abstract class BackendService {
       }
     }
 
-    if (id && id !== item.id) {
+    if (id && id !== this.getItemId(item)) {
       return this.createErrorResponseOptions(url, STATUS.BAD_REQUEST, `Request id does not match item.id`);
     } else {
-      id = item.id;
+      id = this.getItemId(item);
     }
     const existingIx = this.indexOf(collection, id);
     const body = this.bodify(item);
@@ -621,8 +667,8 @@ export abstract class BackendService {
     } else {
       collection[existingIx] = item;
       return this.config.post204 ?
-          { headers, status: STATUS.NO_CONTENT } : // successful; no content
-          { headers, body, status: STATUS.OK }; // successful; return entity
+        { headers, status: STATUS.NO_CONTENT } : // successful; no content
+        { headers, body, status: STATUS.OK }; // successful; return entity
     }
   }
 
@@ -631,14 +677,14 @@ export abstract class BackendService {
   protected put({ collection, collectionName, headers, id, req, url }: RequestInfo): ResponseOptions {
     const item = this.getJsonBody(req);
     // tslint:disable-next-line:triple-equals
-    if (item.id == undefined) {
+    if (this.getItemId(item) == undefined) {
       return this.createErrorResponseOptions(url, STATUS.NOT_FOUND, `Missing '${collectionName}' id`);
     }
-    if (id && id !== item.id) {
+    if (id && id !== this.getItemId(item)) {
       return this.createErrorResponseOptions(url, STATUS.BAD_REQUEST,
         `Request for '${collectionName}' id does not match item.id`);
     } else {
-      id = item.id;
+      id = this.getItemId(item);
     }
     const existingIx = this.indexOf(collection, id);
     const body = this.bodify(item);
@@ -682,6 +728,9 @@ export abstract class BackendService {
       this.db = d;
       this.dbReadySubject.next(true);
     });
+
+    this.setFieldId(this.defineId());
+
     return this.dbReady;
   }
 

src/in-mem/http-backend.service.spec.ts

@@ -18,6 +18,7 @@ import { HttpHeroService } from '../app/http-hero.service';
 
 import { HeroInMemDataService } from '../app/hero-in-mem-data.service';
 import { HeroInMemDataOverrideService } from '../app/hero-in-mem-data-override.service';
+import { HeroInMemDataOverrideIdService } from '../app/hero-in-mem-data-override-id.service';
 import { HeroServiceCoreSpec } from '../app/hero.service.spec';
 
 class Nobody { id: string; name: string; }
@@ -392,6 +393,47 @@ describe('Http Backend Service', () => {
     };
   });
 
+  ////////////////
+  describe('raw Angular Http w/ override id service', () => {
+
+      let http: Http;
+
+      beforeEach(() => {
+        TestBed.configureTestingModule({
+          imports: [
+            HttpModule,
+            HttpInMemoryWebApiModule.forRoot(HeroInMemDataOverrideIdService, { delay })
+          ]
+        });
+
+        http = TestBed.get(Http);
+      });
+
+      it('can get heroes', async(() => {
+        http.get('api/heroes')
+          .map(res => res.json() as Hero[])
+          .subscribe(
+          heroes => {
+            // console.log(heroes);
+            expect(heroes.length).toBeGreaterThan(0, 'should have heroes');
+          },
+          failure
+          );
+      }));
+
+      it('can get heroes by uuid', async(() => {
+        http.get('api/heroes/00000000-0000-0000-0000-000000000002')
+          .map(res => res.json() as Hero)
+          .subscribe(
+          hero => {
+            // console.log(heroes);
+            expect(hero.name).toEqual('Bombasto', 'should find hero Bombasto');
+          },
+          failure
+          );
+      }));
+    });
+
   ////////////////
 
   describe('Http HeroService', () => {