joint.all.js
function reduceRight(collection, callback, accumulator, thisArg) {
      var noaccum = arguments.length < 3;
      callback = baseCreateCallback(callback, thisArg, 4);
      forEachRight(collection, function(value, index, collection) {
        accumulator = noaccum
          ? (noaccum = false, value)
          : callback(accumulator, value, index, collection);
      });
      return accumulator;
    }
function reduceRight(collection, callback, accumulator, thisArg) {
      var noaccum = arguments.length < 3;
      callback = baseCreateCallback(callback, thisArg, 4);
      forEachRight(collection, function(value, index, collection) {
        accumulator = noaccum
          ? (noaccum = false, value)
          : callback(accumulator, value, index, collection);
      });
      return accumulator;
    }
This method is like `_.reduce` except that it iterates over elements
of a `collection` from right to left.

@static
@memberOf _
@alias foldr
@category Collections
@param {Array|Object|string} collection The collection to iterate over.
@param {Function} [callback=identity] The function called per iteration.
@param {*} [accumulator] Initial value of the accumulator.
@param {*} [thisArg] The `this` binding of `callback`.
@returns {*} Returns the accumulated value.
@example

var list = [[0, 1], [2, 3], [4, 5]];
var flat = _.reduceRight(list, function(a, b) { return a.concat(b); }, []);
// => [4, 5, 2, 3, 0, 1]