undersocore.jsを使った合計、平均、中央値の計算

underscore calc

var calc = {
    sum: function(array_num) {
      return _.reduce(array_num, function(memo, num) {
        return memo + (+num);
      }, 0);
    },

    ave: function(array_num) {
      return this.sum(array_num) / array_num.length;
    },

    median: function(array_num) {
      var half = Math.floor(array_num.length/2);
      array_num = _.sortBy(array_num, function(num){
        return num;
      });

      if (array_num.length % 2) {
        return +array_num[half];
      }

      return (+array_num[half - 1] + array_num[half]) / 2;
    }
}