流星，MongoDB的打通认购阵列的一部分

本文介绍了流星，MongoDB的打通认购阵列的一部分的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我有一个关于如何只得到使用的MongoDB和MeteorJS数组的某一个元素的问题。我对用户文档以下模式：

bankList：       {          ID：34567890987654345678          名称：xfgchjbkn          类型：信用       }，       {          ID：09876543456789098767          名称：65789876t8          类型：借记       }    ]

我第一次订阅只有数组中的字段的一部分，特别是我收集所有的ID列表。然后，我有一个编辑屏幕，应该订阅所有字段与匹配的ID阵列中的一个特定元素。我不想暴露阵列仅仅单个元件的其他部分。目前，我使用下面的方法首先收集只是id的列表：

Meteor.users.find（{_ ID：this.userId}，                        {字段：{'bankList.id'：1}}）;

和下面的出版物订阅方法得到的只是一个特定元素的信息：

出版：

Meteor.publish（userBankAdvanced功能（bankId）{      检查（bankId，字符串）;      如果（this.userId）{           返回Meteor.users.find（{_ ID：this.userId，bankList.id：bankId}，{'bankList $'：1}）;      }其他{           this.ready（）;      }  }）;

订阅：

this.route（'edit_account'，{        路径：'/编辑/帐号/'，        waitOn：功能（）{              如果（Session.get（bankId））{                    返回Meteor.subscribe（'userBankAdvanced'，Session.get（bankId））;        }        返回null;        }，        数据：功能（）{              如果（Session.get（bankId））{                返回Meteor.users.findOne（）;        }        返回null;        }，        onBeforeAction：功能（）{              beforeHooks.isRevise（Session.get（bankId））;        }  }）;

订阅方法返回所有与所有的信息数组的元素。我想，例如，仅这（而不是整个所有的信息列表）：

bankList：       {          ID：34567890987654345678          名称：xfgchjbkn          类型：信用       }]

解决方案

看起来你只是缺少你的userBankAdvanced发布功能田说明。我写了一个试验meteorpad使用你的榜样，它似乎很好地工作。银行id是简单有硬codeD。

所以不是

返回Meteor.users.find（{_ ID：this.userId，bankList.id：bankId}，{'bankList $'：1}）;

请尝试使用

返回Meteor.users.find（{_ ID：this.userId，bankList.id：bankId}，{字段：{'bankList $'：1}}）;

I have a question about how to just get a certain element of an array using MongoDB and MeteorJS. I have the following schema for the user document:

bankList:[ { id: "34567890987654345678", name: "xfgchjbkn", type: "credit" }, { id: "09876543456789098767" name: "65789876t8", type: "debit" } ]

I first subscribe to only part of the fields in the array, specifically I gather a list of all the ids. Then I have an edit screen that should subscribe to all of the fields for a specific element in the array with a matching id. I do not want to expose the rest of the array just the single element. Currently, I use the following to first gather a list of just the ids:

Meteor.users.find({_id: this.userId}, {fields:{'bankList.id': 1}});

And the following publication-subscription method to get just a specific element's information:

Publication:

Meteor.publish("userBankAdvanced", function(bankId){ check(bankId,String); if(this.userId){ return Meteor.users.find({_id:this.userId,"bankList.id": bankId}, {'bankList.$': 1}); }else{ this.ready(); } });

Subscription:

this.route('edit_account', { path: '/edit/account/', waitOn: function(){ if(Session.get("bankId")){ return Meteor.subscribe('userBankAdvanced',Session.get("bankId")); } return null; }, data: function(){ if(Session.get("bankId")){ return Meteor.users.findOne(); } return null; }, onBeforeAction: function(){ beforeHooks.isRevise(Session.get("bankId")); } });

The subscription method returns all of the elements of the array with all of the information. I want, for example, just this (not the entire list with all of the information):

bankList:[ { id: "34567890987654345678", name: "xfgchjbkn", type: "credit" }]

解决方案

It looks like you're just missing the "fields" specifier in your "userBankAdvanced" publish function. I wrote a test in meteorpad using your example and it seems to work fine. The bank id is hardcoded for simplicity there.

So instead of

return Meteor.users.find({_id:this.userId,"bankList.id": bankId}, {'bankList.$': 1});

try using

return Meteor.users.find({_id:this.userId,"bankList.id": bankId}, {fields: {'bankList.$': 1}});