feat: implement quantity selector component for improved cart functionality

src/app/features/store/pages/product-detail-page/product-detail-page.component.html

@@ -53,28 +53,13 @@
 
             <section class="product-detail__section">
               <div class="product-detail__purchase">
-                <div class="product-detail__quantity" aria-label="Selector de cantidad">
-                  <button
-                    type="button"
-                    class="product-detail__quantity-button"
-                    aria-label="Disminuir cantidad"
-                    (click)="decreaseQuantity()"
-                  >
-                    -
-                  </button>
-
-                  <span class="product-detail__quantity-value">{{ quantity() }}</span>
-
-                  <button
-                    type="button"
-                    class="product-detail__quantity-button"
-                    aria-label="Aumentar cantidad"
-                    [disabled]="quantity() >= (selectedVariant()?.stock ?? 1)"
-                    (click)="increaseQuantity()"
-                  >
-                    +
-                  </button>
-                </div>
+                <app-quantity-selector
+                  [quantity]="quantity()"
+                  [max]="selectedVariant()?.stock ?? 1"
+                  (increase)="increaseQuantity()"
+                  (decrease)="decreaseQuantity()"
+                  (quantityChange)="quantity.set($event)"
+                />
 
                 <div class="product-detail__actions">
                   <app-button

src/app/features/store/pages/product-detail-page/product-detail-page.component.scss

@@ -62,12 +62,6 @@
     flex-wrap: wrap;
   }
 
-  &__quantity-button {
-    border: 1px solid #dcdcdc;
-    background: #ffffff;
-    color: #666666;
-    transition: border-color 0.2s ease, color 0.2s ease, background-color 0.2s ease;
-  }
 
   &__purchase {
     display: flex;
@@ -76,38 +70,6 @@
     flex-wrap: wrap;
   }
 
-  &__quantity {
-    display: inline-flex;
-    align-items: center;
-    border: 1px solid #d8d8d8;
-    border-radius: 6px;
-    overflow: hidden;
-    min-height: 44px;
-    background: #f6f6f6;
-  }
-
-  &__quantity-button {
-    width: 25px;
-    height: 44px;
-    padding: 0;
-    font-size: 20px;
-    font-weight: 700;
-    line-height: 1;
-    color: #6f6f6f;
-    background: #f6f6f6;
-    border: 0;
-
-  
-  }
-
-  &__quantity-value {
-    min-width: 35px;
-    text-align: center;
-    font-size: 16px;
-    font-weight: 700;
-    line-height: 1;
-    color: #6f6f6f;
-  }
 
   &__actions {
     flex: 1 1 0;

src/app/features/store/pages/product-detail-page/product-detail-page.component.spec.ts

@@ -295,13 +295,13 @@ describe('ProductDetailPageComponent', () => {
     decreaseButton.click();
     fixture.detectChanges();
 
-    expect(element.querySelector('.product-detail__quantity-value')?.textContent?.trim()).toBe('1');
+    expect(element.querySelector('.quantity-selector__value')?.textContent?.trim()).toBe('1');
 
     increaseButton.click();
     increaseButton.click();
     fixture.detectChanges();
 
-    expect(element.querySelector('.product-detail__quantity-value')?.textContent?.trim()).toBe('3');
+    expect(element.querySelector('.quantity-selector__value')?.textContent?.trim()).toBe('3');
   });
 
   it('toggles the full description state when overflow is available', async () => {

src/app/features/store/pages/product-detail-page/product-detail-page.component.ts

@@ -29,11 +29,19 @@ import {
 import { ProductCarouselComponent } from '../../components/product-carousel/product-carousel.component';
 import { ButtonComponent } from '../../../../shared/components/button/button.component';
 import { ProductAttributeSelectorComponent } from '../../components/product-attribute-selector/product-attribute-selector.component';
+import { QuantitySelectorComponent } from '../../../../shared/components/quantity-selector/quantity-selector.component';
 
 @Component({
   selector: 'app-product-detail-page',
   standalone: true,
-  imports: [CommonModule, RouterModule, ProductCarouselComponent, ButtonComponent, ProductAttributeSelectorComponent],
+  imports: [
+    CommonModule,
+    RouterModule,
+    ProductCarouselComponent,
+    ButtonComponent,
+    ProductAttributeSelectorComponent,
+    QuantitySelectorComponent
+  ],
   templateUrl: './product-detail-page.component.html',
   styleUrl: './product-detail-page.component.scss',
   changeDetection: ChangeDetectionStrategy.OnPush

src/app/shared/components/quantity-selector/quantity-selector.component.html

@@ -0,0 +1,23 @@
+<div class="quantity-selector" aria-label="Selector de cantidad">
+  <button
+    type="button"
+    class="quantity-selector__button"
+    aria-label="Disminuir cantidad"
+    [disabled]="quantity() <= min()"
+    (click)="onDecrease()"
+  >
+    -
+  </button>
+
+  <span class="quantity-selector__value">{{ quantity() }}</span>
+
+  <button
+    type="button"
+    class="quantity-selector__button"
+    aria-label="Aumentar cantidad"
+    [disabled]="quantity() >= max()"
+    (click)="onIncrease()"
+  >
+    +
+  </button>
+</div>

src/app/shared/components/quantity-selector/quantity-selector.component.scss

@@ -0,0 +1,47 @@
+:host {
+  display: inline-block;
+}
+
+.quantity-selector {
+  display: inline-flex;
+  align-items: center;
+  border: 1px solid #d8d8d8;
+  border-radius: 6px;
+  overflow: hidden;
+  min-height: 44px;
+  background: #f6f6f6;
+
+  &__button {
+    width: 25px;
+    height: 44px;
+    padding: 0;
+    font-size: 20px;
+    font-weight: 700;
+    line-height: 1;
+    color: #6f6f6f;
+    background: #f6f6f6;
+    border: 0;
+    transition: background-color 0.2s ease, color 0.2s ease;
+    cursor: pointer;
+
+    &:not(:disabled):hover {
+      background-color: #e9e9e9;
+      color: #333333;
+    }
+
+    &:disabled {
+      opacity: 0.4;
+      cursor: not-allowed;
+    }
+  }
+
+  &__value {
+    min-width: 35px;
+    text-align: center;
+    font-size: 16px;
+    font-weight: 700;
+    line-height: 1;
+    color: #6f6f6f;
+    user-select: none;
+  }
+}

src/app/shared/components/quantity-selector/quantity-selector.component.ts

@@ -0,0 +1,35 @@
+import { ChangeDetectionStrategy, Component, input, output } from '@angular/core';
+
+@Component({
+  selector: 'app-quantity-selector',
+  standalone: true,
+  imports: [],
+  templateUrl: './quantity-selector.component.html',
+  styleUrl: './quantity-selector.component.scss',
+  changeDetection: ChangeDetectionStrategy.OnPush
+})
+export class QuantitySelectorComponent {
+  readonly quantity = input<number>(1);
+  readonly min = input<number>(1);
+  readonly max = input<number>(100);
+
+  readonly increase = output<void>();
+  readonly decrease = output<void>();
+  readonly quantityChange = output<number>();
+
+  protected onDecrease(): void {
+    if (this.quantity() > this.min()) {
+      const newValue = this.quantity() - 1;
+      this.decrease.emit();
+      this.quantityChange.emit(newValue);
+    }
+  }
+
+  protected onIncrease(): void {
+    if (this.quantity() < this.max()) {
+      const newValue = this.quantity() + 1;
+      this.increase.emit();
+      this.quantityChange.emit(newValue);
+    }
+  }
+}