Feature: Added the customer module to list / edit customers. This is needed to add the customer discount functionality

bookie/src/app/customers/customer.service.ts

@@ -0,0 +1,58 @@
+import { HttpClient, HttpHeaders } from '@angular/common/http';
+import { Injectable } from '@angular/core';
+import { Observable } from 'rxjs/internal/Observable';
+import { catchError } from 'rxjs/operators';
+
+import { Customer } from '../core/customer';
+import { ErrorLoggerService } from '../core/error-logger.service';
+
+const httpOptions = {
+  headers: new HttpHeaders({ 'Content-Type': 'application/json' }),
+};
+const url = '/api/customers';
+const serviceName = 'CustomerService';
+
+@Injectable({
+  providedIn: 'root',
+})
+export class CustomerService {
+  constructor(private http: HttpClient, private log: ErrorLoggerService) {}
+
+  get(id: string | null): Observable<Customer> {
+    const getUrl: string = id === null ? `${url}` : `${url}/${id}`;
+    return this.http
+      .get<Customer>(getUrl)
+      .pipe(catchError(this.log.handleError(serviceName, `get id=${id}`))) as Observable<Customer>;
+  }
+
+  list(): Observable<Customer[]> {
+    return this.http
+      .get<Customer[]>(`${url}/list`)
+      .pipe(catchError(this.log.handleError(serviceName, 'list'))) as Observable<Customer[]>;
+  }
+
+  save(customer: Customer): Observable<Customer> {
+    return this.http
+      .post<Customer>(`${url}`, customer, httpOptions)
+      .pipe(catchError(this.log.handleError(serviceName, 'save'))) as Observable<Customer>;
+  }
+
+  update(customer: Customer): Observable<Customer> {
+    return this.http
+      .put<Customer>(`${url}/${customer.id}`, customer, httpOptions)
+      .pipe(catchError(this.log.handleError(serviceName, 'update'))) as Observable<Customer>;
+  }
+
+  saveOrUpdate(customer: Customer): Observable<Customer> {
+    if (!customer.id) {
+      return this.save(customer);
+    }
+    return this.update(customer);
+  }
+
+  delete(id: string): Observable<Customer> {
+    return this.http
+      .delete<Customer>(`${url}/${id}`, httpOptions)
+      .pipe(catchError(this.log.handleError(serviceName, 'delete'))) as Observable<Customer>;
+  }
+}