Answer: 5

apps/angular/5-crud-application/src/app/app.component.ts

@@ -1,51 +1,51 @@
 import { CommonModule } from '@angular/common';
-import { HttpClient } from '@angular/common/http';
 import { Component, OnInit } from '@angular/core';
-import { randText } from '@ngneat/falso';
+import { MatProgressSpinnerModule } from '@angular/material/progress-spinner';
+import { MatSnackBarModule } from '@angular/material/snack-bar';
+import { Todo } from './todo.interface';
+import { TodoService } from './todo.service';
 
 @Component({
   standalone: true,
-  imports: [CommonModule],
+  imports: [CommonModule, MatSnackBarModule, MatProgressSpinnerModule],
   selector: 'app-root',
   template: `
-    <div *ngFor="let todo of todos">
-      {{ todo.title }}
-      <button (click)="update(todo)">Update</button>
-    </div>
+    @if (loadingSignal()) {
+      <mat-spinner></mat-spinner>
+    } @else {
+      <div *ngFor="let todo of todosSignal()">
+        {{ todo.title }}
+        <button (click)="updateTodo(todo)">Update</button>
+        <button (click)="deleteTodo(todo.id)">Delete</button>
+      </div>
+    }
   `,
   styles: [],
+  providers: [],
 })
 export class AppComponent implements OnInit {
-  todos!: any[];
+  todosSignal = this.todoService.todosSignal;
+  loadingSignal = this.todoService.loadingSignal;
 
-  constructor(private http: HttpClient) {}
+  constructor(private todoService: TodoService) {}
 
   ngOnInit(): void {
-    this.http
-      .get<any[]>('https://jsonplaceholder.typicode.com/todos')
-      .subscribe((todos) => {
-        this.todos = todos;
-      });
+    this.todoService.getTodos();
   }
 
-  update(todo: any) {
-    this.http
-      .put<any>(
-        `https://jsonplaceholder.typicode.com/todos/${todo.id}`,
-        JSON.stringify({
-          todo: todo.id,
-          title: randText(),
-          body: todo.body,
-          userId: todo.userId,
-        }),
-        {
-          headers: {
-            'Content-type': 'application/json; charset=UTF-8',
-          },
-        },
-      )
-      .subscribe((todoUpdated: any) => {
-        this.todos[todoUpdated.id - 1] = todoUpdated;
-      });
+  updateTodo(todo: Todo) {
+    this.todoService.updateTodo(todo).subscribe((todoUpdated: Todo) => {
+      const updatedTodos = this.todosSignal().filter(
+        (todo) => todo.id !== todoUpdated.id,
+      );
+      this.todosSignal.set(updatedTodos);
+    });
+  }
+
+  deleteTodo(id: number) {
+    this.todoService.deleteTodo(id).subscribe(() => {
+      const allTodos = this.todosSignal().filter((t) => t.id !== id);
+      this.todosSignal.set(allTodos);
+    });
   }
 }

apps/angular/5-crud-application/src/app/app.config.ts

@@ -1,6 +1,16 @@
-import { provideHttpClient } from '@angular/common/http';
+import { HTTP_INTERCEPTORS, provideHttpClient } from '@angular/common/http';
 import { ApplicationConfig } from '@angular/core';
+import { provideAnimations } from '@angular/platform-browser/animations';
+import { GlobalErrorInterceptor } from './error.interceptor';
 
 export const appConfig: ApplicationConfig = {
-  providers: [provideHttpClient()],
+  providers: [
+    provideHttpClient(),
+    provideAnimations(),
+    {
+      provide: HTTP_INTERCEPTORS,
+      useClass: GlobalErrorInterceptor,
+      multi: true,
+    },
+  ],
 };

apps/angular/5-crud-application/src/app/error.interceptor.ts

@@ -0,0 +1,59 @@
+import {
+  HttpErrorResponse,
+  HttpEvent,
+  HttpHandler,
+  HttpInterceptor,
+  HttpRequest,
+} from '@angular/common/http';
+import { Injectable } from '@angular/core';
+import { MatSnackBar } from '@angular/material/snack-bar';
+import { Observable, throwError } from 'rxjs';
+import { catchError } from 'rxjs/operators';
+
+@Injectable()
+export class GlobalErrorInterceptor implements HttpInterceptor {
+  constructor(private snackBar: MatSnackBar) {}
+
+  intercept(
+    request: HttpRequest<any>,
+    next: HttpHandler,
+  ): Observable<HttpEvent<any>> {
+    return next.handle(request).pipe(
+      catchError((error: HttpErrorResponse) => {
+        // Handle different types of errors here
+        let errorMessage = 'An unknown error occurred';
+
+        if (error.error instanceof ErrorEvent) {
+          // Client-side error
+          errorMessage = `Error: ${error.error.message}`;
+        } else {
+          // Server-side error
+          switch (error.status) {
+            case 400:
+              errorMessage = 'Bad request';
+              break;
+            case 401:
+              errorMessage = 'Unauthorized, please log in';
+              break;
+            case 404:
+              errorMessage = 'Resource not found';
+              break;
+            case 500:
+              errorMessage = 'Internal server error';
+              break;
+            default:
+              errorMessage = `Error: ${error.message}`;
+              break;
+          }
+        }
+
+        // Show the error message using MatSnackBar
+        this.snackBar.open(errorMessage, 'Close', {
+          duration: 3000,
+        });
+
+        return throwError(() => new Error());
+      }),
+    );
+  }
+}

apps/angular/5-crud-application/src/app/todo.interface.ts

@@ -0,0 +1,7 @@
+export interface Todo {
+  id: number;
+  title: string;
+  completed: boolean;
+  body: string;
+  userId: number;
+}

apps/angular/5-crud-application/src/app/todo.service.spec.ts

@@ -0,0 +1,16 @@
+import { TestBed } from '@angular/core/testing';
+
+import { TodoService } from './todo.service';
+
+describe('TodoService', () => {
+  let service: TodoService;
+
+  beforeEach(() => {
+    TestBed.configureTestingModule({});
+    service = TestBed.inject(TodoService);
+  });
+
+  it('should be created', () => {
+    expect(service).toBeTruthy();
+  });
+});

apps/angular/5-crud-application/src/app/todo.service.ts

@@ -0,0 +1,51 @@
+import { HttpClient } from '@angular/common/http';
+import { Injectable, signal } from '@angular/core';
+import { randText } from '@ngneat/falso';
+import { finalize, Observable } from 'rxjs';
+import { Todo } from './todo.interface';
+
+@Injectable({
+  providedIn: 'root',
+})
+export class TodoService {
+  private apiUrl = 'https://jsonplaceholder.typicode.com/todos';
+  todosSignal = signal<Todo[]>([]);
+  loadingSignal = signal<boolean>(false);
+
+  constructor(private http: HttpClient) {}
+
+  getTodos(): void {
+    this.loadingSignal.set(true);
+    this.http
+      .get<Todo[]>(this.apiUrl)
+      .pipe(finalize(() => this.loadingSignal.set(false)))
+      .subscribe((data) => this.todosSignal.set(data));
+  }
+
+  updateTodo(todo: Todo): Observable<Todo> {
+    this.loadingSignal.set(true);
+    return this.http
+      .put<Todo>(
+        `${this.apiUrl}/${todo.id}`,
+        JSON.stringify({
+          todo: todo.id,
+          title: randText(),
+          body: todo.body,
+          userId: todo.userId,
+        }),
+        {
+          headers: {
+            'Content-type': 'application/json; charset=UTF-8',
+          },
+        },
+      )
+      .pipe(finalize(() => this.loadingSignal.set(false)));
+  }
+
+  deleteTodo(id: number): Observable<void> {
+    this.loadingSignal.set(true);
+    return this.http
+      .delete<void>(`${this.apiUrl}/${id}`)
+      .pipe(finalize(() => this.loadingSignal.set(false)));
+  }
+}