Method 1.

Using `ngModel`.

@Component({
  selector: 'my-app',template: `
    <div>
      <input type="text" placeholder="Search..."  [(ngModel)]="searchValue">
      <button (click)="clearSearch()">Clear</button>
    </div>
  `,})
export class App {
  searchValue:string = '';
  clearSearch() {
    this.searchValue = null;
  }
}

Plunker code:Plunker1

Method 2.

Using null value instead of empty quotation marks.

 
      
 Plunker code:Plunker2