opt-cc/static/src/app/filter/filter.pipe.ts

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

/**
 * Filter Pipe to filter specific rank by level number in template
 *
 * @author: HardiReady
 */

@Pipe({name: 'rankfilter'})
export class FilterRankPipe implements PipeTransform {

  transform(items: any[], filter: any): any {
    // filter items array, items which match and return true will be kept, false will be filtered out
    const res = items.filter(item => item.level === filter);
    if (res.length === 0) {
      return [{name: '-'}];
    } else {
      return res;
    }
  }

}