Angular 4 search pipe for an array of objects

searchPipe.ts

// *ngFor="let row of (sample | searchPipe: input.value)"
@Pipe({
  name: 'searchPipe',
  pure: false
})
export class SearchPipe implements PipeTransform {
  transform(sample: any[], searchTerm: string): any[] {
    if (!searchTerm) return sample;
    searchTerm = searchTerm.toLowerCase();
    if (sample) {
      return sample.filter(obj => {
        Object.keys(obj).forEach(key => {
          obj[key] = obj[key].toString().toLowerCase();
        });
        return Object.keys(obj).some(key => obj[key].includes(searchTerm));
      });
    }
  }
}