javascript - Meteor mongodb 数据透视和更优雅的代码

Question

我这里有一个包含所有相关详细信息的垃圾箱:http://jsbin.com/ribor/1/edit?js,output

但是为了方便回答，这里有详细信息。我有这些模型示例:

Orders = {
  _id: "T487wBz7Pvzjo2QHh",
  beverages: [
    { 
      _id: "8ea26bb103efae385f80f881",
      delivered: false,
      name: "Wine",
      units: "55"
    }
  ],
  location: "yTKWLFwSDvp3DyCkx",
  locationName: "Ladies Garden",
  locationNumber: "101",
  timestamp: 1398393004864,
  user_id: "W3Fdq36Ts2TdWxCRP",
  username: "jgeezy"
};

Locations = {
  _id: "yTKWLFwSDvp3DyCkx",
  beverages: [
    {
      _id: "e5552a68266ed76895b8228a",
      fillTo: "10",
      name: "Wine Coolers",
      orderWhen: "10",
      startUnits: "10"
    }
  ],
  name: "Teen Cabana",
  number: "103",
  organization: "Super Happy Teens!",
  vendor: false
};

我需要在每个位置的表中呈现一些行，以显示每个位置未交付饮料订单的总数。我已经写好了这个函数:

Template.dashboardOrders.undeliveredOrders = ->
  undeliveredOrders = Orders.find({'beverages.delivered': false}, {
    transform: (order) ->
      order.unfilledOrders = 0
      _.each order.beverages, (bev) ->
        if not bev.delivered
          order.unfilledOrders += 1
      order
  })

但这给了我一个按顺序和时间戳排序的数组。我正在寻找的输出是一个按唯一位置和时间戳排序的数组。不完全确定如何到达那里，但我一直在尝试不同的映射和减少方法，因为我觉得这是要走的路，但我被困住了。非常感谢任何帮助!

奖励 另外，我的方法感觉不太优雅，因为必须返回订单对象并使用 += 来递增。我感觉可能有更好的方法来做到这一点。

Answer 1

我只是要添加第二个答案来回答 @jasongonzales 的第二个问题。我的第一个答案，只是查询，返回所有未交付的订单，并按位置和时间戳对它们进行排序。根据评论，还需要以下内容:

I want to include all the orders that are undelivered per location and I need a count of the undelivered orders per location.

有很多方法可以实现这一目标。我认为最简单的方法是不要尝试将所有内容都挤入查询中，而是处理查询返回的数据:

Template.dashboardOrders.undeliveredOrdersByLocation = ->
  orders = Orders.find
      beverages.delivered: no
    ,
      sort:
        location: 1
        timestamp: 1

  # Create an object, locations, to hold the undelivered orders by location;
  # the object keys are the location _id's, and the values are the mongo docs:
  locations = {}

  # Loop through all the undelivered orders and add each to the locations object:
  orders.forEach (doc) ->
    unless locations[doc.location]?
      locations[doc.location] =
        undeliveredOrders: []
        undeliveredOrdersCount: 0
        location: doc.location
        locationName: doc.locationName
        locationNumber: doc.locationNumber
        # etc., whatever else your template needs

    locations[doc.location].undeliveredOrders.push doc
    locations[doc.location].undeliveredOrdersCount++

  # Convert the locations object into an array for use in your template:
  return _.values(locations) # Don't need to preserve the keys

您没有提供模板的示例，但您可以像这样使用 locations 数组:

{{#each undeliveredOrdersByLocation}}
  There are {{undeliveredOrdersCount}} undelivered orders for {{locationName}}:
    {{#each undeliveredOrders}}
      An order submitted by {{username}} on {{timestamp}} for:
        <ul>
          {{#each beverages}}
            <li>{{units}} units of {{name}} need to be delivered.</li>
          {{/each}}
        </ul>
    {{/each}}
{{/each}}