Underscore有 _。groupBy 功能应该完全符合您的要求：

Underscore has the _.groupBy function which should do exactly what you want:

var groups = _.groupBy(occurences, function (date) {
  return moment(date).startOf('day').format();
});

这将返回一个对象，其中每个键都是一天，值是一个包含所有出现次数的数组那天。

This will return an object where each key is a day and the value an array containing all the occurrences for that day.

要将对象转换为与问题中相同形式的数组，您可以使用map：

To transform the object into an array of the same form as in the question you could use map:

var result = _.map(groups, function(group, day){
    return {
        day: day,
        times: group
    }
});

要进行分组，映射和排序，您可以执行以下操作：

To group, map and sort you could do something like:

var occurrenceDay = function(occurrence){
    return moment(occurrence).startOf('day').format();
};

var groupToDay = function(group, day){
    return {
        day: day,
        times: group
    }
};

var result = _.chain(occurences)
    .groupBy(occurrenceDay)
    .map(groupToDay)
    .sortBy('day')
    .value();