_get_brands_(cursor, direction) {

    if ( direction === 'next') {

      if ( cursor === 0) {
        this.brands_collection = this.afs.collection('brands', ref =>
          ref.orderBy('created')
            .limit(5)
        );
        return this.brands = this.brands_collection.valueChanges();

      } else {

        this.brands_collection = this.afs.collection('brands', ref =>
          ref.orderBy('created')
            .startAfter(cursor)
            .limit(5)
        );
        return this.brands = this.brands_collection.valueChanges();
      }

    } else if (direction === 'back') {

      console.log('Back pagination start ==> ', cursor);
      this.brands_collection = this.afs.collection('brands', ref =>
        ref.orderBy('created')
          .endBefore(cursor)
          .limit(5)
      );

      return this.brands = this.brands_collection.valueChanges();
    }
  }