如何在角度管道中获取已过滤记录的计数

import { Component } from '@angular/core';

@Component({
  selector: 'app-your-component',
  templateUrl: './your-component.component.html',
  styleUrls: ['./your-component.component.css']
})
export class YourComponent {
  records: any[] = [
    { name: 'Record 1', category: 'Category 1' },
    { name: 'Record 2', category: 'Category 2' },
    { name: 'Record 3', category: 'Category 1' },
    { name: 'Record 4', category: 'Category 2' },
    { name: 'Record 5', category: 'Category 3' }
  ];

  filteredRecords: any[];

  filterRecords(category: string) {
    this.filteredRecords = this.records.filter(record => record.category === category);
  }
}

<div>
  <label>Filter by category:</label>
  <select (change)="filterRecords($event.target.value)">
    <option value="">All</option>
    <option value="Category 1">Category 1</option>
    <option value="Category 2">Category 2</option>
    <option value="Category 3">Category 3</option>
  </select>
</div>

<p>Filtered records count: {{ filteredRecords.length }}</p>

<ul>
  <li *ngFor="let record of filteredRecords">{{ record.name }}</li>
</ul>