feat(doc): move scroll-vd

apps/performance/scroll-cd/src/app/app.component.ts

@@ -0,0 +1,53 @@
+import { AsyncPipe, NgIf } from '@angular/common';
+import { Component, HostListener } from '@angular/core';
+import { BehaviorSubject } from 'rxjs';
+
+@Component({
+  standalone: true,
+  imports: [NgIf, AsyncPipe],
+  selector: 'app-root',
+  template: `
+    <div>Top</div>
+    <div>Middle</div>
+    <div>Bottom</div>
+    <button (click)="goToTop()" *ngIf="displayButton$ | async">Top</button>
+  `,
+  styles: [
+    `
+      :host {
+        height: 1500px;
+        display: flex;
+        flex-direction: column;
+        justify-content: space-between;
+
+        button {
+          position: fixed;
+          bottom: 1rem;
+          left: 1rem;
+          z-index: 1;
+          padding: 1rem;
+        }
+      }
+    `,
+  ],
+})
+export class AppComponent {
+  title = 'scroll-cd';
+
+  private displayButtonSubject = new BehaviorSubject<boolean>(false);
+  displayButton$ = this.displayButtonSubject.asObservable();
+
+  @HostListener('window:scroll', ['$event'])
+  onScroll() {
+    const pos = window.pageYOffset;
+    this.displayButtonSubject.next(pos > 50);
+  }
+
+  goToTop() {
+    window.scroll({
+      top: 0,
+      left: 0,
+      behavior: 'smooth',
+    });
+  }
+}