<input type="search" class="form-control" placeholder="Search file" (keyup)="onSearch($) [(ngModel)]='searchKeywords'>

onSearch(event: any) {
    const keywords = event.target.value;
    if (keywords && keywords.length > 2) {
          const apiURL =`abc/thg/hjy?filter[file.name]=${keywords}`;
          this.api.get(apiURL).subscribe((data: any) => {
            console.log(data);
            this.topics = data.list;
            if (this.trigger) {
            this.trigger.openMenu();
            }
         });
    } else {
        this.topics = [];
        this.trigger.closeMenu();
    }
}