sortedGroupBy using Underscore

README.md

sortedGroupBy

jsFiddle Example

Convenience function for performing a groupBy on a list then a sortBy on the resulting groups using Underscore methods.

sortedGroupBy(list, groupByIterator, sortByIterator)

sortedGroupBy.coffee

sortedGroupBy = (list, groupByIter, sortByIter) ->
  # Pass in an array to group by multiple object keys
  if _.isArray(groupByIter)
    groupBy = (obj) ->
      _.map groupByIter, (key, value) -> obj[key]
  else
    groupBy = groupByIter

  # Pass in an array to sort by multiple object keys
  if _.isArray(sortByIter)
    sortBy = (obj) ->
      _.map sortByIter, (key, value) -> obj[key]
  else
    sortBy = sortByIter

  groups = _.groupBy(list, groupBy)
  _.each groups, (value, key, list) ->
    list[key] = _.sortBy(value, sortBy)

  return groups

sortedGroupBy.js

function sortedGroupBy(list, groupByIter, sortByIter) {
    if (_.isArray(groupByIter)) {
        function groupBy(obj) {
            return _.map(groupByIter, function(key, value) {
                return obj[key];
            });
        }
    } else {
        var groupBy = groupByIter;
    }
    if (_.isArray(sortByIter)) {
        function sortBy(obj) {
            return _.map(sortByIter, function(key, value) {
                return obj[key];
            });
        }
    } else {
        var sortBy = sortByIter;
    }
    var groups = _.groupBy(list, groupBy);
    _.each(groups, function(value, key, list) {
        list[key] = _.sortBy(value, sortBy);
    });
    return groups;
}