Angular 2+ pipe to filter items based on value of a single prop

filterBy.filter.ts

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

@Pipe({
  name: 'filterBy'
})
export class FilterByFilter implements PipeTransform {
  transform(list, arg: string) {
    if (!list) {
      return [];
    }
    if (!arg) {
      return list;
    }

    return list.filter(item => this.check(item, arg.split('.')));
  }

  private check(item: {}, path: string[]) {
    const [first, ...rest] = path;
    if (path.length === 0) {
      return false;
    }
    if (path.length === 1) {
      return item[first];
    }
    if (path.length > 1) {
      return this.check(item[first], rest);
    }
  }
}