我有一个mongoose模式，它有一个包含项目的数组和另一个数组

var mongoose = require('mongoose');
var Schema = mongoose.Schema;

var CompanySchema = new Schema({

  dateCreated: { type: Date, default: Date.now },

  ownerId: { type: String },

  ceo: { type: String },

  shareHolders: [{
    userId: { type: String },
    shares: { type: Number, default: 0 },
    role: { type: String },
    agreements: [{
      agreementID: { type: String },
    }]
  }],

  team: [{
      userId:     { type: String },
      position:   { type: String }

  }],


});

module.exports = mongoose.model('Company', CompanySchema);

我尝试先检查一下shareholder数组中是否有一个包含userID特定值的项，然后我需要更新shareholder项并将一个新的agreementID推送到agreement数组中。我花了相当多的时间在Google上搜索和交换堆栈，但似乎无法实现这一点。
这是我到目前为止所拥有的，顺便说一句，这似乎总是创造一个新的股东，从来没有更新现有的股东。
更新股东我正在尝试这个

Company.update({
      "_id": req.companyID,
      "shareHolders.userId": req.userID
    }, {
      $push: {
        "shareHolders.$.agreements.agreementID": req.agreementID
      }
    }, {
      $set: {
        "shareHolders.$.shares": ++req.shares
      }
    },
    function(err) {

      if (err) {
        callback(err, err);
      } else {
        callback(null, 'success');
      }
    })

要查找股东是否存在，这总是导致股东不存在，并创建新股东

function checkShareHolder() {
    console.log('checkShareHolder');
    var date = moment().format('MM/DD/YYYY');
    var data = {
      companyID: agreement.applicant.applicantCompanyID,
      userID: agreement.coSigner.coSignerID
    }

    company_worker.getCompanyByID(agreement.applicant.applicantCompanyID, function(err, result) {

      if (err) {
        console.log(err);
        res.send(err);
      } else {

        company = result;
        console.log('checkShareHolder');
        process.nextTick(function() {
          looper()
        });

      }

    })

    function looper() {

      var updateShareholder = 'false';
      var addShareHolder = 'false';
      console.log('looper');
      console.log(company.shareHolders);

      if (company.shareHolders.length > 0) {

        async.forEach(company.shareHolders, function(item, callback) {

          console.log(item);
          if (item.userID == agreement.coSigner.coSignerID) {
            console.log('updateShareholder = true'),
              updateShareholder = 'true',
              callback()

          } else(
            console.log('addShareHolder = true'),
            addShareHolder = 'true',
            callback()

          )

        }, function(err) {

          if (err) {
            console.log(err);
          }

          if (addShareHolder == 'true') {
            console.log('looper addShareHolder');
            process.nextTick(function() {
              addShareholder()
            });
          } else if (updateShareholder == 'true') {
            console.log('looper updateShareholder');
            process.nextTick(function() {
              updateShareholder()
            });
          }

        });
      } else {

        console.log('looper addShareHolder as nothing found');
        process.nextTick(function() {
          addShareholder()
        });

      }

    }

  };