Answer:1

apps/angular/1-projection/src/app/component/city-card/city-card.component.ts

@@ -1,12 +1,48 @@
-import { Component, OnInit } from '@angular/core';
+import { Component, inject, OnInit, Signal } from '@angular/core';
+import { CityStore } from '../../data-access/city.store';
+import {
+  FakeHttpService,
+  randomCity,
+} from '../../data-access/fake-http.service';
+import { City } from '../../model/city.model';
+import { CardComponent } from '../../ui/card/card.component';
+import { ListItemComponent } from '../../ui/list-item/list-item.component';
 
 @Component({
   selector: 'app-city-card',
-  template: 'TODO City',
-  imports: [],
+  template: `
+    <app-card
+      [list]="cities()"
+      [customClass]="'rgba(0, 0, 250, 0.1)'"
+      [templateRef]="city"
+      (add)="addCity()">
+      <img src="assets/img/city.png" width="200px" />
+    </app-card>
+
+    <ng-template #city let-city>
+      <app-list-item
+        [name]="city.name"
+        [id]="city.id"
+        (delete)="deleteCity(city.id)" />
+    </ng-template>
+  `,
+  imports: [CardComponent, ListItemComponent],
 })
 export class CityCardComponent implements OnInit {
-  constructor() {}
+  private http: FakeHttpService = inject(FakeHttpService);
+  private store: CityStore = inject(CityStore);
+
+  cities: Signal<City[]> = this.store.elements$;
+
+  ngOnInit(): void {
+    this.http.fetchCities$.subscribe((c) => this.store.addAll(c));
+  }
+
+  addCity() {
+    this.store.addOne(randomCity());
+  }
 
-  ngOnInit(): void {}
+  deleteCity(cityId: number) {
+    this.store.deleteOne(cityId);
+  }
 }

apps/angular/1-projection/src/app/component/student-card/student-card.component.ts

@@ -1,39 +1,48 @@
-import { Component, OnInit } from '@angular/core';
-import { FakeHttpService } from '../../data-access/fake-http.service';
+import { Component, inject, OnInit, Signal } from '@angular/core';
+import {
+  FakeHttpService,
+  randStudent,
+} from '../../data-access/fake-http.service';
 import { StudentStore } from '../../data-access/student.store';
-import { CardType } from '../../model/card.model';
 import { Student } from '../../model/student.model';
 import { CardComponent } from '../../ui/card/card.component';
+import { ListItemComponent } from '../../ui/list-item/list-item.component';
 
 @Component({
   selector: 'app-student-card',
   template: `
     <app-card
-      [list]="students"
-      [type]="cardType"
-      customClass="bg-light-green"></app-card>
+      [list]="students()"
+      [customClass]="'rgba(0, 250, 0, 0.1)'"
+      [templateRef]="student"
+      (add)="addStudent()">
+      <img src="assets/img/student.webp" width="200px" />
+    </app-card>
+
+    <ng-template #student let-student>
+      <app-list-item
+        [name]="student.firstName"
+        [id]="student.id"
+        (delete)="deleteStudent(student.id)" />
+    </ng-template>
   `,
-  styles: [
-    `
-      ::ng-deep .bg-light-green {
-        background-color: rgba(0, 250, 0, 0.1);
-      }
-    `,
-  ],
-  imports: [CardComponent],
+  imports: [CardComponent, ListItemComponent],
 })
 export class StudentCardComponent implements OnInit {
-  students: Student[] = [];
-  cardType = CardType.STUDENT;
+  private http: FakeHttpService = inject(FakeHttpService);
+  private store: StudentStore = inject(StudentStore);
 
-  constructor(
-    private http: FakeHttpService,
-    private store: StudentStore,
-  ) {}
+  students: Signal<Student[]> = this.store.elements$;
 
   ngOnInit(): void {
     this.http.fetchStudents$.subscribe((s) => this.store.addAll(s));
+  }
+
+  addStudent() {
+    this.store.addOne(randStudent());
+  }
 
-    this.store.students$.subscribe((s) => (this.students = s));
+  deleteStudent(studentId: number) {
+    this.store.deleteOne(studentId);
   }
 }

apps/angular/1-projection/src/app/component/teacher-card/teacher-card.component.ts

@@ -1,39 +1,48 @@
-import { Component, OnInit } from '@angular/core';
-import { FakeHttpService } from '../../data-access/fake-http.service';
+import { Component, inject, OnInit, Signal } from '@angular/core';
+import {
+  FakeHttpService,
+  randTeacher,
+} from '../../data-access/fake-http.service';
 import { TeacherStore } from '../../data-access/teacher.store';
-import { CardType } from '../../model/card.model';
 import { Teacher } from '../../model/teacher.model';
 import { CardComponent } from '../../ui/card/card.component';
+import { ListItemComponent } from '../../ui/list-item/list-item.component';
 
 @Component({
   selector: 'app-teacher-card',
   template: `
     <app-card
-      [list]="teachers"
-      [type]="cardType"
-      customClass="bg-light-red"></app-card>
+      [list]="teachers()"
+      [customClass]="'rgba(250, 0, 0, 0.1)'"
+      [templateRef]="teacher"
+      (add)="addTeacher()">
+      <img src="assets/img/teacher.png" width="200px" />
+    </app-card>
+
+    <ng-template #teacher let-teacher>
+      <app-list-item
+        [name]="teacher.firstName"
+        [id]="teacher.id"
+        (delete)="deleteTeacher(teacher.id)" />
+    </ng-template>
   `,
-  styles: [
-    `
-      ::ng-deep .bg-light-red {
-        background-color: rgba(250, 0, 0, 0.1);
-      }
-    `,
-  ],
-  imports: [CardComponent],
+  imports: [CardComponent, ListItemComponent],
 })
 export class TeacherCardComponent implements OnInit {
-  teachers: Teacher[] = [];
-  cardType = CardType.TEACHER;
+  private http: FakeHttpService = inject(FakeHttpService);
+  private store: TeacherStore = inject(TeacherStore);
 
-  constructor(
-    private http: FakeHttpService,
-    private store: TeacherStore,
-  ) {}
+  teachers: Signal<Teacher[]> = this.store.elements$;
 
   ngOnInit(): void {
     this.http.fetchTeachers$.subscribe((t) => this.store.addAll(t));
+  }
+
+  addTeacher() {
+    this.store.addOne(randTeacher());
+  }
 
-    this.store.teachers$.subscribe((t) => (this.teachers = t));
+  deleteTeacher(teacherId: number) {
+    this.store.deleteOne(teacherId);
   }
 }

apps/angular/1-projection/src/app/data-access/city.store.ts

@@ -1,23 +1,8 @@
 import { Injectable } from '@angular/core';
-import { BehaviorSubject } from 'rxjs';
 import { City } from '../model/city.model';
+import { Store } from './store';
 
 @Injectable({
   providedIn: 'root',
 })
-export class CityStore {
-  private cities = new BehaviorSubject<City[]>([]);
-  cities$ = this.cities.asObservable();
-
-  addAll(cities: City[]) {
-    this.cities.next(cities);
-  }
-
-  addOne(student: City) {
-    this.cities.next([...this.cities.value, student]);
-  }
-
-  deleteOne(id: number) {
-    this.cities.next(this.cities.value.filter((s) => s.id !== id));
-  }
-}
+export class CityStore extends Store<City> {}

apps/angular/1-projection/src/app/data-access/store.ts

@@ -0,0 +1,23 @@
+import { signal } from '@angular/core';
+
+export class Store<T extends { id: number }> {
+  private elements = signal<T[]>([]);
+  elements$ = this.elements.asReadonly();
+
+  addAll(elements: T[]) {
+    this.elements.update((currentElements) => [
+      ...currentElements,
+      ...elements,
+    ]);
+  }
+
+  addOne(element: T) {
+    this.elements.update((currentElements) => [...currentElements, element]);
+  }
+
+  deleteOne(id: number) {
+    this.elements.update((currentElements) =>
+      currentElements.filter((t) => t.id !== id),
+    );
+  }
+}

apps/angular/1-projection/src/app/data-access/student.store.ts

@@ -1,23 +1,8 @@
 import { Injectable } from '@angular/core';
-import { BehaviorSubject } from 'rxjs';
 import { Student } from '../model/student.model';
+import { Store } from './store';
 
 @Injectable({
   providedIn: 'root',
 })
-export class StudentStore {
-  private students = new BehaviorSubject<Student[]>([]);
-  students$ = this.students.asObservable();
-
-  addAll(students: Student[]) {
-    this.students.next(students);
-  }
-
-  addOne(student: Student) {
-    this.students.next([...this.students.value, student]);
-  }
-
-  deleteOne(id: number) {
-    this.students.next(this.students.value.filter((s) => s.id !== id));
-  }
-}
+export class StudentStore extends Store<Student> {}

apps/angular/1-projection/src/app/data-access/teacher.store.ts

@@ -1,23 +1,8 @@
 import { Injectable } from '@angular/core';
-import { BehaviorSubject } from 'rxjs';
 import { Teacher } from '../model/teacher.model';
+import { Store } from './store';
 
 @Injectable({
   providedIn: 'root',
 })
-export class TeacherStore {
-  private teachers = new BehaviorSubject<Teacher[]>([]);
-  teachers$ = this.teachers.asObservable();
-
-  addAll(teachers: Teacher[]) {
-    this.teachers.next(teachers);
-  }
-
-  addOne(teacher: Teacher) {
-    this.teachers.next([...this.teachers.value, teacher]);
-  }
-
-  deleteOne(id: number) {
-    this.teachers.next(this.teachers.value.filter((t) => t.id !== id));
-  }
-}
+export class TeacherStore extends Store<Teacher> {}

apps/angular/1-projection/src/app/ui/card/card.component.ts

@@ -1,60 +1,35 @@
-import { NgFor, NgIf } from '@angular/common';
-import { Component, Input } from '@angular/core';
-import { randStudent, randTeacher } from '../../data-access/fake-http.service';
-import { StudentStore } from '../../data-access/student.store';
-import { TeacherStore } from '../../data-access/teacher.store';
-import { CardType } from '../../model/card.model';
-import { ListItemComponent } from '../list-item/list-item.component';
+import { NgTemplateOutlet } from '@angular/common';
+import { Component, input, output, TemplateRef } from '@angular/core';
 
 @Component({
   selector: 'app-card',
   template: `
     <div
       class="flex w-fit flex-col gap-3 rounded-md border-2 border-black p-4"
-      [class]="customClass">
-      <img
-        *ngIf="type === CardType.TEACHER"
-        src="assets/img/teacher.png"
-        width="200px" />
-      <img
-        *ngIf="type === CardType.STUDENT"
-        src="assets/img/student.webp"
-        width="200px" />
+      [style.background-color]="customClass()">
+      <ng-content select="img" />
 
       <section>
-        <app-list-item
-          *ngFor="let item of list"
-          [name]="item.firstName"
-          [id]="item.id"
-          [type]="type"></app-list-item>
+        @for (item of list(); track item.id) {
+          <ng-container
+            [ngTemplateOutlet]="templateRef()"
+            [ngTemplateOutletContext]="{ $implicit: item }"></ng-container>
+        }
       </section>
 
       <button
         class="rounded-sm border border-blue-500 bg-blue-300 p-2"
-        (click)="addNewItem()">
+        (click)="add.emit()">
         Add
       </button>
     </div>
   `,
-  imports: [NgIf, NgFor, ListItemComponent],
+  imports: [NgTemplateOutlet],
 })
 export class CardComponent {
-  @Input() list: any[] | null = null;
-  @Input() type!: CardType;
-  @Input() customClass = '';
+  list = input<{ id: number }[] | null>(null);
+  customClass = input<string>('');
+  templateRef = input.required<TemplateRef<any>>();
 
-  CardType = CardType;
-
-  constructor(
-    private teacherStore: TeacherStore,
-    private studentStore: StudentStore,
-  ) {}
-
-  addNewItem() {
-    if (this.type === CardType.TEACHER) {
-      this.teacherStore.addOne(randTeacher());
-    } else if (this.type === CardType.STUDENT) {
-      this.studentStore.addOne(randStudent());
-    }
-  }
+  add = output<void>();
 }