Answer:1 projection with signals and all v17 features

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

@@ -1,40 +1,52 @@
-import { Component, OnInit } from '@angular/core';
-import { FakeHttpService } from '../../data-access/fake-http.service';
+import { AsyncPipe } from '@angular/common';
+import { ChangeDetectionStrategy, Component, inject } 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 { CardRowDirective } from '../../ui/card/card-row.directive';
 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>
+    <app-card [items]="students()" (add)="addStudent()" class="bg-light-green">
+      <img src="assets/img/student.webp" width="200px" />
+      <ng-template [cardRow]="students()" let-student>
+        <app-list-item (delete)="deleteStudent(student.id)">
+          {{ student.firstName }}
+        </app-list-item>
+      </ng-template>
+    </app-card>
   `,
   standalone: true,
   styles: [
     `
-      ::ng-deep .bg-light-green {
+      .bg-light-green {
         background-color: rgba(0, 250, 0, 0.1);
       }
     `,
   ],
-  imports: [CardComponent],
+  imports: [CardComponent, ListItemComponent, AsyncPipe, CardRowDirective],
+  changeDetection: ChangeDetectionStrategy.OnPush,
 })
-export class StudentCardComponent implements OnInit {
-  students: Student[] = [];
-  cardType = CardType.STUDENT;
+export class StudentCardComponent {
+  private http = inject(FakeHttpService);
+  private store = inject(StudentStore);
 
-  constructor(
-    private http: FakeHttpService,
-    private store: StudentStore,
-  ) {}
+  students = this.store.students;
 
-  ngOnInit(): void {
+  constructor() {
     this.http.fetchStudents$.subscribe((s) => this.store.addAll(s));
+  }
+
+  addStudent() {
+    this.store.addOne(randStudent());
+  }
 
-    this.store.students$.subscribe((s) => (this.students = s));
+  deleteStudent(id: number) {
+    this.store.deleteOne(id);
   }
 }

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

@@ -1,40 +1,52 @@
-import { Component, OnInit } from '@angular/core';
-import { FakeHttpService } from '../../data-access/fake-http.service';
+import { AsyncPipe } from '@angular/common';
+import { ChangeDetectionStrategy, Component, inject } 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 { CardRowDirective } from '../../ui/card/card-row.directive';
 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>
+    <app-card [items]="teachers()" class="bg-light-red" (add)="addTeacher()">
+      <img src="assets/img/teacher.png" width="200px" />
+      <ng-template [cardRow]="teachers()" let-teacher>
+        <app-list-item (delete)="deleteTeacher(teacher.id)">
+          {{ teacher.firstName }}
+        </app-list-item>
+      </ng-template>
+    </app-card>
   `,
   styles: [
     `
-      ::ng-deep .bg-light-red {
+      .bg-light-red {
         background-color: rgba(250, 0, 0, 0.1);
       }
     `,
   ],
   standalone: true,
-  imports: [CardComponent],
+  imports: [ListItemComponent, AsyncPipe, CardRowDirective, CardComponent],
+  changeDetection: ChangeDetectionStrategy.OnPush,
 })
-export class TeacherCardComponent implements OnInit {
-  teachers: Teacher[] = [];
-  cardType = CardType.TEACHER;
+export class TeacherCardComponent {
+  private http = inject(FakeHttpService);
+  private store = inject(TeacherStore);
 
-  constructor(
-    private http: FakeHttpService,
-    private store: TeacherStore,
-  ) {}
+  teachers = this.store.teachers;
 
-  ngOnInit(): void {
+  constructor() {
     this.http.fetchTeachers$.subscribe((t) => this.store.addAll(t));
+  }
+
+  addTeacher() {
+    this.store.addOne(randTeacher());
+  }
 
-    this.store.teachers$.subscribe((t) => (this.teachers = t));
+  deleteTeacher(id: number) {
+    this.store.deleteOne(id);
   }
 }

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

@@ -1,23 +1,21 @@
-import { Injectable } from '@angular/core';
-import { BehaviorSubject } from 'rxjs';
+import { Injectable, signal } from '@angular/core';
 import { Student } from '../model/student.model';
 
 @Injectable({
   providedIn: 'root',
 })
 export class StudentStore {
-  private students = new BehaviorSubject<Student[]>([]);
-  students$ = this.students.asObservable();
+  students = signal<Student[]>([]);
 
   addAll(students: Student[]) {
-    this.students.next(students);
+    this.students.set(students);
   }
 
   addOne(student: Student) {
-    this.students.next([...this.students.value, student]);
+    this.students.set([...this.students(), student]);
   }
 
   deleteOne(id: number) {
-    this.students.next(this.students.value.filter((s) => s.id !== id));
+    this.students.set(this.students().filter((s) => s.id !== id));
   }
 }

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

@@ -1,23 +1,21 @@
-import { Injectable } from '@angular/core';
-import { BehaviorSubject } from 'rxjs';
+import { Injectable, signal } from '@angular/core';
 import { Teacher } from '../model/teacher.model';
 
 @Injectable({
   providedIn: 'root',
 })
 export class TeacherStore {
-  private teachers = new BehaviorSubject<Teacher[]>([]);
-  teachers$ = this.teachers.asObservable();
+  teachers = signal<Teacher[]>([]);
 
   addAll(teachers: Teacher[]) {
-    this.teachers.next(teachers);
+    this.teachers.set(teachers);
   }
 
   addOne(teacher: Teacher) {
-    this.teachers.next([...this.teachers.value, teacher]);
+    this.teachers.set([...this.teachers(), teacher]);
   }
 
   deleteOne(id: number) {
-    this.teachers.next(this.teachers.value.filter((t) => t.id !== id));
+    this.teachers.set(this.teachers().filter((t) => t.id !== id));
   }
 }

apps/angular/projection/src/app/model/card.model.ts

@@ -1,5 +0,0 @@
-export enum CardType {
-  TEACHER,
-  STUDENT,
-  CITY,
-}

apps/angular/projection/src/app/ui/card/card-row.directive.ts

@@ -0,0 +1,17 @@
+import { Directive, input } from '@angular/core';
+
+interface CardRowContext<T> {
+  $implicit: T;
+}
+
+@Directive({ selector: 'ng-template[cardRow]', standalone: true })
+export class CardRowDirective<T> {
+  cardRow = input.required<T[]>();
+
+  static ngTemplateContextGuard<TContext>(
+    dir: CardRowDirective<TContext>,
+    ctx: unknown,
+  ): ctx is CardRowContext<TContext> {
+    return true;
+  }
+}

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

@@ -1,61 +1,43 @@
-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 {
+  ChangeDetectionStrategy,
+  Component,
+  contentChild,
+  input,
+  output,
+  TemplateRef,
+} from '@angular/core';
+import { CardRowDirective } from './card-row.directive';
 
 @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" />
+    <ng-content select="img" />
 
-      <section>
-        <app-list-item
-          *ngFor="let item of list"
-          [name]="item.firstName"
-          [id]="item.id"
-          [type]="type"></app-list-item>
-      </section>
+    <section>
+      @for (item of items(); track item.id) {
+        <ng-template
+          [ngTemplateOutlet]="rowTemplate()"
+          [ngTemplateOutletContext]="{ $implicit: item }"></ng-template>
+      }
+    </section>
 
-      <button
-        class="rounded-sm border border-blue-500 bg-blue-300 p-2"
-        (click)="addNewItem()">
-        Add
-      </button>
-    </div>
+    <button
+      class="rounded-sm border border-blue-500 bg-blue-300 p-2"
+      (click)="add.emit()">
+      Add
+    </button>
   `,
   standalone: true,
-  imports: [NgIf, NgFor, ListItemComponent],
+  imports: [NgTemplateOutlet],
+  host: {
+    class: 'border-2 border-black rounded-md p-4 w-fit flex flex-col gap-3',
+  },
+  changeDetection: ChangeDetectionStrategy.OnPush,
 })
-export class CardComponent {
-  @Input() list: any[] | null = null;
-  @Input() type!: CardType;
-  @Input() customClass = '';
+export class CardComponent<T extends { id: number }> {
+  items = input.required<T[]>();
+  add = output();
 
-  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());
-    }
-  }
+  rowTemplate = contentChild.required(CardRowDirective, { read: TemplateRef });
 }

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

@@ -1,35 +1,18 @@
-import { Component, Input } from '@angular/core';
-import { StudentStore } from '../../data-access/student.store';
-import { TeacherStore } from '../../data-access/teacher.store';
-import { CardType } from '../../model/card.model';
+import { ChangeDetectionStrategy, Component, output } from '@angular/core';
 
 @Component({
   selector: 'app-list-item',
   template: `
     <div class="border-grey-300 flex justify-between border px-2 py-1">
-      {{ name }}
-      <button (click)="delete(id)">
+      <ng-content />
+      <button (click)="delete.emit()">
         <img class="h-5" src="assets/svg/trash.svg" />
       </button>
     </div>
   `,
   standalone: true,
+  changeDetection: ChangeDetectionStrategy.OnPush,
 })
 export class ListItemComponent {
-  @Input() id!: number;
-  @Input() name!: string;
-  @Input() type!: CardType;
-
-  constructor(
-    private teacherStore: TeacherStore,
-    private studentStore: StudentStore,
-  ) {}
-
-  delete(id: number) {
-    if (this.type === CardType.TEACHER) {
-      this.teacherStore.deleteOne(id);
-    } else if (this.type === CardType.STUDENT) {
-      this.studentStore.deleteOne(id);
-    }
-  }
+  delete = output<void>();
 }