函数柯里化

var cost = (function () {
        var args = [];
        return function () {
          if (arguments.length === 0) {
            var money = 0;
            for (var i = 0; i < args.length; i++) {
              money += args[i];
            }
            console.log(money);
            return money;
          } else {
            [].push.apply(args, arguments);
            console.log(args);
          }
        };
      })();
      cost(100)
      cost(100)
      cost(100)
      cost()