code: function equalOwnProperties(left, right, equalityComparer) {
          if (left === right)
              return true;
          if (!left || !right)
              return false;
          for (var key in left)
              if (hasOwnProperty.call(left, key)) {
                  if (!hasOwnProperty.call(right, key) === undefined)
                      return false;
                  if (equalityComparer ? !equalityComparer(left[key], right[key]) : left[key] !== right[key])
                      return false;
              }
          for (var key in right)
              if (hasOwnProperty.call(right, key)) {
                  if (!hasOwnProperty.call(left, key))
                      return false;
              }
          return true;
      }
docs: Performs a shallow equality comparison of the contents of two map-likes.
  
  @param left A map-like whose properties should be compared.
  @param right A map-like whose properties should be compared.