code: function map(arr, fun, thisp) {
          var i,
              length = arr.length,
              result = [];
          for (i = 0; i < length; i += 1) {
              if (arr.hasOwnProperty(i)) {
                  result[i] = fun.call(thisp, arr[i], i, arr);
              }
          }
          return result;
      }
docs: Equivalent to Array.prototype.map