code: function arrayDiff(arrayTarget, arrayCheck) {
      if (!(arrayTarget instanceof Array) || !(arrayCheck instanceof Array)) {
          throw new Error('Both objects have to be an array');
      }
  
      return arrayTarget.filter(item => !~arrayCheck.indexOf(item));
  }
docs: Determines which elements from arrayTarget are not present in arrayCheck.
  
  @param {array} arrayTarget Target of the check
  @param {array} arrayCheck Subject of the check
  @returns {array}