MongoDB Aggregate()-错误"TypeError:无法调用未定义的方法'forEach'" [英] MongoDB aggregate() - error "TypeError: Cannot call method 'forEach' of undefined"

问题描述

我在"script.js"中有以下脚本:

I have the following scrip in "script.js"

conn = new Mongo();
db = conn.getDB("learn");
db.contracts.aggregate([
  { $match: { regionCode: '77' } },
  { $unwind: '$products' },
  { 
    $project: {  
      _id: '$_id',
      regNum: '$regNum',  
      prodName: '$products.name',  
      prodPrice: '$products.price'
    }
  },
  { $match: { 'prodName' : 'Water' } }
], {cursor:{}}).result.forEach(printjson);

我通过以下方式在命令提示符下运行它

I run it from the command prompt by the following way

mongo script.js >> out.txt

mongo script.js >> out.txt

在文件"out.txt"中出现错误

In file "out.txt" I have the error

TypeError:无法在script.js中调用未定义的方法'forEach'

TypeError: Cannot call method 'forEach' of undefined at script.js

当我从mongo shell mongo.exe(通过使用load())运行脚本时，同样的问题.

The same problem, when I run the script from mongo shell mongo.exe (by using load()).

当我从Robomongo 0.8.4运行相同的聚合命令时，我获得了成功的结果(3个json格式的文档).有人知道，为什么会发生这种情况?

When I run the same aggregate command from the Robomongo 0.8.4 I have succesive result (3 documents in json format). Does anybody know, why this may happen?

Mongodb版本2.6.5

Mongodb version 2.6.5

推荐答案

您需要在没有result变量访问权限的情况下运行它.在shell中访问时，mongodb返回的cursor没有名为result的属性，因此会出现错误.

You need to run it without the result variable access. The cursor returned by mongodb when accessed in the shell, does not have a property named result and hence you get the error.

db.contracts.aggregate([
  { $match: { regionCode: '77' } },
  { $unwind: '$products' },
  { 
    $project: {  
      _id: '$_id',
      regNum: '$regNum',  
      prodName: '$products.name',  
      prodPrice: '$products.price'
    }
  },
  { $match: { 'prodName' : 'Water' } }
], {cursor:{}}).forEach(printjson);

这篇关于MongoDB Aggregate()-错误"TypeError:无法调用未定义的方法'forEach'"的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！