mongoose.js:我如何从引用的子数组中删除一个属性，同时使用填充和使用其中一个子数组字段作为过滤器

我有下面的代码在node js使用猫鼬包。

1)如果我使用填充方法，我如何在响应的基础数组中删除字段总数?因为该数组是由对另一个集合的引用组成的。

2)我如何使用"活动"。字段来过滤只有"ACTIVE"作为状态的活动?

定义:

地基模型

var mongoose=require('mongoose');
var Schema = mongoose.Schema;
var foundation = new Schema({
     twitter_account:{type: String, required: true, unique: true},
     name:{type: String, required: true, unique: true},
     pic_path: {type: String, required: true},
     doc_path: {type: String, required: true},
     campaigns: [{type: Schema.ObjectId, ref: 'Campaign'}]
},{
    timestamps: true
});
module.exports = mongoose.model('Foundation', foundation);

在campaign模型中，我有Foundations字段，这是一个对Foundations的引用数组，我想在响应中删除它以避免冗余

var campaign = new Schema({
.............
     foundations: [{type: Schema.ObjectId, ref: 'Foundation'}],
......................
}

这是我检索数据的API的路由

var express = require('express');
var router = express.Router();
var Foundation=require('../models/Foundation');
var mongoose= require('mongoose');
var Promise = require("bluebird");
var _ = require('lodash');

//get all Foundations
router.get('/get/all', function(req, res, next) {
  var results=Foundation.find({},{twitter_account:1,name:1,campaigns:1})
  .populate('campaigns').exec(function (err, foundation) {
        if (err) return handleError(err);
        console.log(foundation);
        res.send(foundation);
});
});
module.exports = router;

下面是响应:

[
  {
    "_id": "58229b253e1ad628e1ed975e",
    "twitter_account": "@YYYYYYYYYYYY",
    "name": "YYYYYYYYYYYY",
    "campaigns": [
      {
        "_id": "5822a9444aea133044b6eb84",
        "updatedAt": "2016-11-09T04:42:44.922Z",
        "createdAt": "2016-11-09T04:42:44.922Z",
         "total": 0,
        "state": "ACTIVE",
        "__v": 0,
        "end_date": null,
        "foundations": [
          "58229b253e1ad628e1ed975e",
          "58229b253e1ad628e1ed975f"
        ]
      },
      {
        "_id": "5822a9444aea133044b6eb85",
        "updatedAt": "2016-11-09T04:42:44.925Z",
        "createdAt": "2016-11-09T04:42:44.925Z",
        "remaining_ammount_to_goal": 500000,
        "total": 0,
        "state": "ACTIVE",
        "__v": 0,
        "end_date": null,
        "foundations": [
          "58229b253e1ad628e1ed975e"
        ]
      }
    ]
  },
  {
    "_id": "58229b253e1ad628e1ed975f",
    "twitter_account": "@XXXXXXXXXXX",
    "name": "XXXXXXXXX",
    "campaigns": [
      {
        "_id": "5822a9444aea133044b6eb85",
        "updatedAt": "2016-11-09T04:42:44.925Z",
        "createdAt": "2016-11-09T04:42:44.925Z",
        "total": 0,
        "state": "ACTIVE",
        "__v": 0,
        "end_date": null,
        "foundations": [
          "58229b253e1ad628e1ed975e"
        ]
      }
    ]

期望的响应(只是想在活动对象中删除基础数组字段):

[
  {
    "_id": "58229b253e1ad628e1ed975e",
    "twitter_account": "@YYYYYYYYYYYY",
    "name": "YYYYYYYYYYYY",
    "campaigns": [
      {
        "_id": "5822a9444aea133044b6eb84",
        "updatedAt": "2016-11-09T04:42:44.922Z",
        "createdAt": "2016-11-09T04:42:44.922Z",
         "total": 0,
        "state": "ACTIVE",
        "__v": 0,
        "end_date": null
      },
      {
        "_id": "5822a9444aea133044b6eb85",
        "updatedAt": "2016-11-09T04:42:44.925Z",
        "createdAt": "2016-11-09T04:42:44.925Z",
        "remaining_ammount_to_goal": 500000,
        "total": 0,
        "state": "ACTIVE",
        "__v": 0,
        "end_date": null
      }
    ]
  },
  {
    "_id": "58229b253e1ad628e1ed975f",
    "twitter_account": "@XXXXXXXXXXX",
    "name": "XXXXXXXXX",
    "campaigns": [
      {
        "_id": "5822a9444aea133044b6eb85",
        "updatedAt": "2016-11-09T04:42:44.925Z",
        "createdAt": "2016-11-09T04:42:44.925Z",
        "total": 0,
        "state": "ACTIVE",
        "__v": 0,
        "end_date": null
      }
    ]

任何想法?。非常感谢!!

EDIT:为了将来的参考，使用填充来过滤"campaign"JSONArray上具有state="Active"的对象，我实现了使用:var =结果Foundation.find ({}, {twitter_account: 1、名称:1、活动:1})

  .populate({path : 'campaigns' ,select :'-foundations', match:{state:'ACTIVE'}}).exec(function (err, foundation) {
        if (err) return handleError(err);
        console.log(foundation);
        res.send(foundation);
});