compile js file with transpilator (v6 => v5)

gistfile1.js

"use strict";
var Item = function Item(game) {
  this.game = game;
  this.number = 1;
  this.equipped = 0;
};
($traceurRuntime.createClass)(Item, {
  load: function(data) {
    for (var i in data) {
      this[i] = data[i];
    }
    return this;
  },
  action: function(fn) {
    if (this.canUse()) {
      if (this.number > 1) {
        this.number--;
      } else {
        _.remove(this.game.items.list, this);
      }
    } else {
      throw "CANNOT USE";
    }
    if (this.game.battle.isBattle) {
      this.game.characters.stopFighting();
      fn();
      this.game.characters.autoFighting();
    } else {
      fn();
    }
  },
  getPrice: function() {
    return this.price;
  },
  canBuy: function() {
    return (this.game.gils >= this.getPrice());
  },
  buy: function() {
    if (this.canBuy()) {
      this.game.gils -= this.getPrice();
      this.game.items.add(this);
    }
  },
  inStock: function() {
    var sum = 0;
    for (var $__1 = this.game.items.list[Symbol.iterator](),
        $__2; !($__2 = $__1.next()).done; ) {
      var i = $__2.value;
      {
        if (i.name === this.name) {
          sum += i.number;
        }
      }
    }
    return sum;
  },
  canEquip: function() {
    return (this.game.items.getEquipped().length < this.game.items.MAX_ITEMS);
  },
  equip: function() {
    this.equipped = this.number;
  },
  unequip: function() {
    this.equipped = 0;
  },
  export: function() {
    var json = _.pick(this, 'number', 'equipped');
    json.model = this.constructor.name;
    return json;
  }
}, {});