来自API的角度搜索过滤器文本不起作用

Question

我是Angular的新手，我需要过滤来自API的值。我尝试过这种方式。但我得到ERROR TypeError: items.filter is not a function，请您帮我解决这个问题。

HTML

 <div class="container">
    <div class="row mt-4 mb-3">
      <div class="col-md-8">
        <div class="input-group mb-3">
          <input type="text" [(ngModel)]="searchText">
          <div class="input-group-append">
            <button id="btncat-search" class="btn btn-primary p-3" type="button">Search</button>
          </div>
        </div>
      </div>
    </div>

    <div>
      <div>

        <div *ngFor="let cat of categories, let i=index"  [ngClass]="((i % 2)==0) ? 'col-md-5 left-col':'col-md-4'">
          <div>
            <button type="button" class="btn">{{cat.name | filter : searchText}}</button>
            <i class="fa fa-chevron-right"></i>
          </div>
        </div>
      </div>
    </div>
  </div>

PIPE.TS

import { Pipe, PipeTransform } from '@angular/core';

@Pipe({
    name: 'filter'
})
export class FilterPipe implements PipeTransform {
    transform(items: any[], searchText: string): any[] {
        if(!items) return [];
        if(!searchText) return items;
    searchText = searchText.toLowerCase();
    return items.filter( it => {
          return it.toLowerCase().includes(searchText);
        });
       }
}