code: function _isEqualArray(a, b) {
          if (a === b) {
              return true;
          }
          if ((a === undefined) || (b === undefined)) {
              return false;
          }
          var i = a.length;
          if (i !== b.length){
              return false;
          }
          while (i--) {
              if (a[i] !== b[i]) {
                  return false;
              }
          }
          return true;
      }
docs: Compares two arrays for equality.