Answer:1 Projection (done refactoring of card component)

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

@@ -1,9 +1,60 @@
-import { ChangeDetectionStrategy, Component } from '@angular/core';
+import { NgOptimizedImage } from '@angular/common';
+import {
+  ChangeDetectionStrategy,
+  Component,
+  inject,
+  WritableSignal,
+} from '@angular/core';
+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';
+import { CityStore } from './../../data-access/city.store';
 
 @Component({
   selector: 'app-city-card',
-  template: 'TODO City',
-  imports: [],
+  template: `
+    <app-card
+      customClass="bg-light-blue"
+      [list]="cities()"
+      [template]="listItem"
+      (addNewItem)="addNewItem()">
+      <img
+        card-header
+        ngSrc="assets/img/city.png"
+        width="200"
+        height="200"
+        alt="" />
+    </app-card>
+
+    <ng-template #listItem let-item>
+      <app-list-item
+        [name]="item.name"
+        [id]="item.id"
+        (deleteItem)="deleteItem($event)" />
+    </ng-template>
+  `,
+  imports: [CardComponent, NgOptimizedImage, ListItemComponent],
   changeDetection: ChangeDetectionStrategy.OnPush,
 })
-export class CityCardComponent {}
+export class CityCardComponent {
+  private http: FakeHttpService = inject(FakeHttpService);
+  private store: CityStore = inject(CityStore);
+
+  protected cities: WritableSignal<City[]> = this.store.cities;
+
+  ngOnInit(): void {
+    this.http.fetchCities$.subscribe((s) => this.store.addAll(s));
+  }
+
+  public addNewItem(): void {
+    this.store.addOne(randomCity());
+  }
+
+  public deleteItem(id: number): void {
+    this.store.deleteOne(id);
+  }
+}

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

@@ -1,40 +1,61 @@
+import { NgOptimizedImage } from '@angular/common';
 import {
   ChangeDetectionStrategy,
   Component,
   inject,
   OnInit,
+  WritableSignal,
 } from '@angular/core';
-import { FakeHttpService } from '../../data-access/fake-http.service';
+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
+      customClass="bg-light-green"
       [list]="students()"
-      [type]="cardType"
-      customClass="bg-light-green" />
+      [template]="listItem"
+      (addNewItem)="addNewItem()">
+      <img
+        card-header
+        ngSrc="assets/img/student.webp"
+        width="200"
+        height="200"
+        alt="" />
+    </app-card>
+
+    <ng-template #listItem let-item>
+      <app-list-item
+        [name]="item.firstName"
+        [id]="item.id"
+        (deleteItem)="deleteItem($event)" />
+    </ng-template>
   `,
-  styles: [
-    `
-      ::ng-deep .bg-light-green {
-        background-color: rgba(0, 250, 0, 0.1);
-      }
-    `,
-  ],
-  imports: [CardComponent],
+  imports: [CardComponent, NgOptimizedImage, ListItemComponent],
   changeDetection: ChangeDetectionStrategy.OnPush,
 })
 export class StudentCardComponent implements OnInit {
-  private http = inject(FakeHttpService);
-  private store = inject(StudentStore);
+  private http: FakeHttpService = inject(FakeHttpService);
+  private store: StudentStore = inject(StudentStore);
 
-  students = this.store.students;
-  cardType = CardType.STUDENT;
+  protected students: WritableSignal<Student[]> = this.store.students;
 
   ngOnInit(): void {
     this.http.fetchStudents$.subscribe((s) => this.store.addAll(s));
   }
+
+  public addNewItem(): void {
+    this.store.addOne(randStudent());
+  }
+
+  public deleteItem(id: number): void {
+    this.store.deleteOne(id);
+  }
 }

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

@@ -1,40 +1,61 @@
+import { NgOptimizedImage } from '@angular/common';
 import {
   ChangeDetectionStrategy,
   Component,
   inject,
   OnInit,
+  WritableSignal,
 } from '@angular/core';
-import { FakeHttpService } from '../../data-access/fake-http.service';
+import {
+  FakeHttpService,
+  randTeacher,
+} from '../../data-access/fake-http.service';
 import { TeacherStore } from '../../data-access/teacher.store';
-import { CardType } from '../../model/card.model';
 import { CardComponent } from '../../ui/card/card.component';
+import { ListItemComponent } from '../../ui/list-item/list-item.component';
+import { Teacher } from './../../model/teacher.model';
 
 @Component({
   selector: 'app-teacher-card',
   template: `
     <app-card
       [list]="teachers()"
-      [type]="cardType"
-      customClass="bg-light-red"></app-card>
+      [template]="listItem"
+      (addNewItem)="addNewItem()"
+      customClass="bg-light-red">
+      <img
+        card-header
+        ngSrc="assets/img/teacher.png"
+        width="200"
+        height="200"
+        alt="" />
+    </app-card>
+
+    <ng-template #listItem let-item>
+      <app-list-item
+        [name]="item.firstName"
+        [id]="item.id"
+        (deleteItem)="deleteItem($event)" />
+    </ng-template>
   `,
-  styles: [
-    `
-      ::ng-deep .bg-light-red {
-        background-color: rgba(250, 0, 0, 0.1);
-      }
-    `,
-  ],
   changeDetection: ChangeDetectionStrategy.Eager,
-  imports: [CardComponent],
+  imports: [CardComponent, NgOptimizedImage, ListItemComponent],
 })
 export class TeacherCardComponent implements OnInit {
-  private http = inject(FakeHttpService);
-  private store = inject(TeacherStore);
+  private http: FakeHttpService = inject(FakeHttpService);
+  private store: TeacherStore = inject(TeacherStore);
 
-  teachers = this.store.teachers;
-  cardType = CardType.TEACHER;
+  protected teachers: WritableSignal<Teacher[]> = this.store.teachers;
 
   ngOnInit(): void {
     this.http.fetchTeachers$.subscribe((t) => this.store.addAll(t));
   }
+
+  public addNewItem(): void {
+    this.store.addOne(randTeacher());
+  }
+
+  public deleteItem(id: number): void {
+    this.store.deleteOne(id);
+  }
 }

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

@@ -5,7 +5,7 @@ import { City } from '../model/city.model';
   providedIn: 'root',
 })
 export class CityStore {
-  private cities = signal<City[]>([]);
+  public cities = signal<City[]>([]);
 
   addAll(cities: City[]) {
     this.cities.set(cities);

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

@@ -1,64 +1,70 @@
-import { NgOptimizedImage } from '@angular/common';
+import { NgTemplateOutlet } from '@angular/common';
 import {
   ChangeDetectionStrategy,
   Component,
-  inject,
   input,
+  InputSignal,
+  output,
+  OutputEmitterRef,
+  TemplateRef,
 } 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 { City } from '../../model/city.model';
+import { Student } from '../../model/student.model';
+import { Teacher } from '../../model/teacher.model';
+interface CardTemplateContext {
+  $implicit: TCardTuple;
+}
+
+type TCardTuple = Student | Teacher | City;
 
 @Component({
   selector: 'app-card',
   template: `
     <div
       class="flex w-fit flex-col gap-3 rounded-md border-2 border-black p-4"
       [class]="customClass()">
-      @if (type() === CardType.TEACHER) {
-        <img ngSrc="assets/img/teacher.png" width="200" height="200" alt="" />
-      }
-      @if (type() === CardType.STUDENT) {
-        <img ngSrc="assets/img/student.webp" width="200" height="200" alt="" />
-      }
+      <ng-content select="[card-header]" />
 
       <section>
         @for (item of list(); track item) {
-          <app-list-item
-            [name]="item.firstName"
-            [id]="item.id"
-            [type]="type()"></app-list-item>
+          <ng-container
+            [ngTemplateOutlet]="template()"
+            [ngTemplateOutletContext]="{ $implicit: item }" />
         }
       </section>
 
       <button
         class="rounded-sm border border-blue-500 bg-blue-300 p-2"
-        (click)="addNewItem()">
+        (click)="onAddNewItem($event)">
         Add
       </button>
     </div>
   `,
+  styles: [
+    `
+      .bg-light-green {
+        background-color: rgba(0, 250, 0, 0.1);
+      }
+      .bg-light-red {
+        background-color: rgba(250, 0, 0, 0.1);
+      }
+      .bg-light-blue {
+        background-color: rgba(0, 0, 250, 0.1);
+      }
+    `,
+  ],
   changeDetection: ChangeDetectionStrategy.Eager,
-  imports: [ListItemComponent, NgOptimizedImage],
+  imports: [NgTemplateOutlet],
 })
 export class CardComponent {
-  private teacherStore = inject(TeacherStore);
-  private studentStore = inject(StudentStore);
+  public addNewItem: OutputEmitterRef<Event> = output<Event>();
 
-  readonly list = input<any[] | null>(null);
-  readonly type = input.required<CardType>();
+  public template: InputSignal<TemplateRef<CardTemplateContext>> =
+    input.required<TemplateRef<CardTemplateContext>>();
+  readonly list = input<TCardTuple[] | null>(null);
   readonly customClass = input('');
 
-  CardType = CardType;
-
-  addNewItem() {
-    const type = this.type();
-    if (type === CardType.TEACHER) {
-      this.teacherStore.addOne(randTeacher());
-    } else if (type === CardType.STUDENT) {
-      this.studentStore.addOne(randStudent());
-    }
+  public onAddNewItem(event: Event): void {
+    this.addNewItem.emit(event);
   }
 }

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

@@ -1,39 +1,31 @@
 import {
   ChangeDetectionStrategy,
   Component,
-  inject,
   input,
+  InputSignal,
+  output,
+  OutputEmitterRef,
 } from '@angular/core';
-import { StudentStore } from '../../data-access/student.store';
-import { TeacherStore } from '../../data-access/teacher.store';
-import { CardType } from '../../model/card.model';
 
 @Component({
   selector: 'app-list-item',
   template: `
     <div class="flex justify-between border border-gray-300 px-2 py-1">
       {{ name() }}
-      <button (click)="delete(id())">
+      <button (click)="onDeleteItem(id())">
         <img class="h-5" src="assets/svg/trash.svg" alt="trash" />
       </button>
     </div>
   `,
   changeDetection: ChangeDetectionStrategy.OnPush,
 })
 export class ListItemComponent {
-  private teacherStore = inject(TeacherStore);
-  private studentStore = inject(StudentStore);
+  public deleteItem: OutputEmitterRef<number> = output<number>();
 
-  readonly id = input.required<number>();
-  readonly name = input.required<string>();
-  readonly type = input.required<CardType>();
+  readonly id: InputSignal<number> = input.required<number>();
+  readonly name: InputSignal<string> = input.required<string>();
 
-  delete(id: number) {
-    const type = this.type();
-    if (type === CardType.TEACHER) {
-      this.teacherStore.deleteOne(id);
-    } else if (type === CardType.STUDENT) {
-      this.studentStore.deleteOne(id);
-    }
+  public onDeleteItem(id: number): void {
+    this.deleteItem.emit(id);
   }
 }