限制在ng中重复，但搜索整个数组

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

@Component({
  selector: 'app-root',
  template: `
    <input type="text" [(ngModel)]="searchTerm" (input)="onSearch()" placeholder="Search...">
    <ul>
      <li *ngFor="let item of filteredItems">{{ item }}</li>
    </ul>
  `
})
export class AppComponent {
  items = ['apple', 'banana', 'apple', 'orange', 'banana', 'grape'];
  searchTerm = '';
  filteredItems = [];

  ngOnInit() {
    this.filteredItems = [...new Set(this.items)]; // 去重
  }

  onSearch() {
    if (this.searchTerm) {
      this.filteredItems = this.items.filter(item => 
        item.toLowerCase().includes(this.searchTerm.toLowerCase())
      );
    } else {
      this.filteredItems = [...new Set(this.items)]; // 搜索框清空时重新去重
    }
  }
}