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

@Injectable()
@Pipe({name: 'union'})
export class UnionPipe implements PipeTransform {

  transform(arr:any[], args:any[] = []):any[] {
    return args.reduce((newArr, currArr) =>
        newArr.concat(currArr.reduce((noDupArr, curr) =>
            ((!~noDupArr.indexOf(curr) && !~newArr.indexOf(curr))
              ? noDupArr.push(curr)
              : noDupArr, noDupArr)
        , [])
      ), arr);
  }
}