feat(challenge 54): refactor the application to be a fully signal-based

Author: truonghungit

apps/signal/54-pipe-observable-to-signal/src/app/currency.pipe.ts

@@ -1,5 +1,4 @@
 import { inject, Pipe, PipeTransform } from '@angular/core';
-import { map, Observable } from 'rxjs';
 import { CurrencyService } from './currency.service';
 
 @Pipe({
@@ -8,7 +7,9 @@ import { CurrencyService } from './currency.service';
 export class CurrencyPipe implements PipeTransform {
   currencyService = inject(CurrencyService);
 
-  transform(price: number): Observable<string> {
-    return this.currencyService.symbol$.pipe(map((s) => `${price}${s}`));
+  transform(price: number, currencyCode: string): string {
+    const symbol = this.currencyService.getSymbol(currencyCode);
+
+    return `${price}${symbol}`;
   }
 }

apps/signal/54-pipe-observable-to-signal/src/app/currency.service.ts

@@ -1,5 +1,4 @@
 import { Injectable } from '@angular/core';
-import { BehaviorSubject, map } from 'rxjs';
 
 export interface Currency {
   name: string;
@@ -17,14 +16,7 @@ export const currency: Currency[] = [
 
 @Injectable()
 export class CurrencyService {
-  private code = new BehaviorSubject('EUR');
-
-  readonly code$ = this.code.asObservable();
-  readonly symbol$ = this.code$.pipe(
-    map((code) => currency.find((c) => c.code === code)?.symbol ?? code),
-  );
-
-  public updateCode(code: string) {
-    this.code.next(code);
+  getSymbol(code: string): string {
+    return currency.find((c) => c.code === code)?.symbol ?? code;
   }
 }

apps/signal/54-pipe-observable-to-signal/src/app/product-row.component.ts

@@ -1,9 +1,8 @@
-import { AsyncPipe } from '@angular/common';
 import {
   ChangeDetectionStrategy,
   Component,
-  inject,
-  Input,
+  computed,
+  input,
 } from '@angular/core';
 import { CurrencyPipe } from './currency.pipe';
 import { CurrencyService } from './currency.service';
@@ -13,22 +12,17 @@ import { Product } from './product.model';
   // eslint-disable-next-line @angular-eslint/component-selector
   selector: 'tr[product-row]',
   template: `
-    <td>{{ productInfo.name }}</td>
-    <td>{{ productInfo.priceA | currency | async }}</td>
-    <td>{{ productInfo.priceB | currency | async }}</td>
-    <td>{{ productInfo.priceC | currency | async }}</td>
+    <td>{{ product().name }}</td>
+    <td>{{ product().priceA | currency: currencyCode() }}</td>
+    <td>{{ product().priceB | currency: currencyCode() }}</td>
+    <td>{{ product().priceC | currency: currencyCode() }}</td>
   `,
-  imports: [AsyncPipe, CurrencyPipe],
+  imports: [CurrencyPipe],
   providers: [CurrencyService],
   changeDetection: ChangeDetectionStrategy.OnPush,
 })
 export class ProductRowComponent {
-  protected productInfo!: Product;
+  product = input.required<Product>();
 
-  @Input({ required: true }) set product(product: Product) {
-    this.currencyService.updateCode(product.currencyCode);
-    this.productInfo = product;
-  }
-
-  currencyService = inject(CurrencyService);
+  currencyCode = computed(() => this.product().currencyCode);
 }

libs/shared/ui/src/lib/table.component.ts

@@ -1,9 +1,10 @@
+import { NgTemplateOutlet } from '@angular/common';
 import { Component, contentChild, input, TemplateRef } from '@angular/core';
 
 @Component({
   // eslint-disable-next-line @angular-eslint/component-selector
   selector: 'table',
-  imports: [],
+  imports: [NgTemplateOutlet],
   template: `
     <thead>
       <ng-container *ngTemplateOutlet="headerTemplate()"></ng-container>