feat(Answer:1): refactor according to comments

Author: Fakhriddin Abdurakhimov

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

@@ -1,4 +1,4 @@
-import { Component, OnInit } from '@angular/core';
+import { Component, OnInit, computed, inject } from '@angular/core';
 import { CityStore } from '../../data-access/city.store';
 import {
   FakeHttpService,
@@ -11,7 +11,7 @@ import { CardComponent } from '../../ui/card/card.component';
   selector: 'app-city-card',
   template: `
     <app-card
-      [list]="cityListItems"
+      [list]="cityListItems()"
       class="bg-light-green"
       (addNewItemEvent)="handleAddNewItemEvent()"
       (deleteItemEvent)="handleDeleteItemEvent($event)">
@@ -30,23 +30,18 @@ import { CardComponent } from '../../ui/card/card.component';
   imports: [CardComponent],
 })
 export class CityCardComponent implements OnInit {
-  cityListItems: CardListItem[] = [];
+  private http = inject(FakeHttpService);
+  private store = inject(CityStore);
 
-  constructor(
-    private http: FakeHttpService,
-    private store: CityStore,
-  ) {}
+  cityListItems = computed<CardListItem[]>(() =>
+    this.store.cities().map((city) => ({
+      name: city.name,
+      id: city.id,
+    })),
+  );
 
   ngOnInit(): void {
     this.http.fetchCities$.subscribe((e) => this.store.addAll(e));
-    this.store.cities$.subscribe((cities) => {
-      this.cityListItems = cities.map((city) => {
-        return {
-          name: city.name,
-          id: city.id,
-        };
-      });
-    });
   }
 
   handleAddNewItemEvent() {

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

@@ -1,4 +1,4 @@
-import { Component, OnInit } from '@angular/core';
+import { Component, OnInit, computed, inject } from '@angular/core';
 import {
   FakeHttpService,
   randStudent,
@@ -11,7 +11,7 @@ import { CardComponent } from '../../ui/card/card.component';
   selector: 'app-student-card',
   template: `
     <app-card
-      [list]="studentListItems"
+      [list]="studentListItems()"
       class="bg-light-green"
       (addNewItemEvent)="handleAddNewItemEvent()"
       (deleteItemEvent)="handleDeleteItemEvent($event)">
@@ -30,24 +30,20 @@ import { CardComponent } from '../../ui/card/card.component';
   imports: [CardComponent],
 })
 export class StudentCardComponent implements OnInit {
-  studentListItems: CardListItem[] = [];
+  private http = inject(FakeHttpService);
+  private store = inject(StudentStore);
 
-  constructor(
-    private http: FakeHttpService,
-    private store: StudentStore,
-  ) {}
+  students = this.store.students;
+
+  studentListItems = computed<CardListItem[]>(() =>
+    this.store.students().map((student) => ({
+      name: student.firstName,
+      id: student.id,
+    })),
+  );
 
   ngOnInit(): void {
     this.http.fetchStudents$.subscribe((s) => this.store.addAll(s));
-
-    this.store.students$.subscribe((students) => {
-      this.studentListItems = students.map((student) => {
-        return {
-          name: student.firstName,
-          id: student.id,
-        };
-      });
-    });
   }
 
   handleAddNewItemEvent() {

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

@@ -1,4 +1,4 @@
-import { Component, OnInit } from '@angular/core';
+import { Component, OnInit, computed, inject } from '@angular/core';
 import {
   FakeHttpService,
   randTeacher,
@@ -11,7 +11,7 @@ import { CardComponent } from '../../ui/card/card.component';
   selector: 'app-teacher-card',
   template: `
     <app-card
-      [list]="teacherListItems"
+      [list]="teacherListItems()"
       class="bg-light-red"
       (addNewItemEvent)="handleAddNewItemEvent()"
       (deleteItemEvent)="handleDeleteItemEvent($event)">
@@ -30,24 +30,17 @@ import { CardComponent } from '../../ui/card/card.component';
   imports: [CardComponent],
 })
 export class TeacherCardComponent implements OnInit {
-  teacherListItems: CardListItem[] = [];
+  private http = inject(FakeHttpService);
+  private store = inject(TeacherStore);
 
-  constructor(
-    private http: FakeHttpService,
-    private store: TeacherStore,
-  ) {}
+  teacherListItems = computed<CardListItem[]>(() =>
+    this.store
+      .teachers()
+      .map((teacher) => ({ name: teacher.firstName, id: teacher.id })),
+  );
 
   ngOnInit(): void {
     this.http.fetchTeachers$.subscribe((t) => this.store.addAll(t));
-
-    this.store.teachers$.subscribe((teachers) => {
-      this.teacherListItems = teachers.map((teacher) => {
-        return {
-          name: teacher.firstName,
-          id: teacher.id,
-        };
-      });
-    });
   }
 
   handleAddNewItemEvent() {

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

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

apps/angular/1-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();
+  public 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/1-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();
+  public 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/1-projection/src/app/ui/card/card.component.ts

@@ -1,5 +1,4 @@
-import { NgFor } from '@angular/common';
-import { Component, EventEmitter, Input, Output } from '@angular/core';
+import { Component, input, output } from '@angular/core';
 import { CardListItem } from '../../model/card.model';
 import { ListItemComponent } from '../list-item/list-item.component';
 
@@ -8,27 +7,28 @@ import { ListItemComponent } from '../list-item/list-item.component';
   template: `
     <ng-content select="[card-img]"></ng-content>
     <section>
-      <app-list-item
-        *ngFor="let item of list"
-        [name]="item.name"
-        [id]="item.id"
-        (deleteItemEvent)="handleDeleteItemEvent($event)"></app-list-item>
+      @for (item of list(); track $index) {
+        <app-list-item
+          [name]="item.name"
+          [id]="item.id"
+          (deleteItemEvent)="handleDeleteItemEvent($event)" />
+      }
     </section>
     <button
       class="rounded-sm border border-blue-500 bg-blue-300 p-2"
       (click)="addNewItem()">
       Add
     </button>
   `,
-  imports: [NgFor, ListItemComponent],
+  imports: [ListItemComponent],
   host: {
     class: 'border-2 border-black rounded-md p-4 w-fit flex flex-col gap-3',
   },
 })
 export class CardComponent {
-  @Input() list: CardListItem[] | null = null;
-  @Output() deleteItemEvent = new EventEmitter<number>();
-  @Output() addNewItemEvent = new EventEmitter<void>();
+  list = input<CardListItem[]>([]);
+  deleteItemEvent = output<number>();
+  addNewItemEvent = output<void>();
 
   addNewItem() {
     this.addNewItemEvent.emit();

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

@@ -1,21 +1,21 @@
-import { Component, EventEmitter, Input, Output } from '@angular/core';
+import { Component, input, 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)">
+      {{ name() }}
+      <button (click)="delete(id())">
         <img class="h-5" src="assets/svg/trash.svg" />
       </button>
     </div>
   `,
   standalone: true,
 })
 export class ListItemComponent {
-  @Input() id!: number;
-  @Input() name!: string;
-  @Output() deleteItemEvent = new EventEmitter<number>();
+  id = input.required<number>();
+  name = input.required<string>();
+  deleteItemEvent = output<number>();
 
   delete(id: number) {
     this.deleteItemEvent.emit(id);