Question 118673 in Mongodb Question posted in
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Mongodb – Mongoose group nested object

Say I have a collection of people with a person object and its associated data.

{  
   _id: '1'
   person:{
    email:"[email protected]"
    traveled_to: 'North Korea',
    someinfo:"random"
    
   }

}

{  
   _id: '2'
   person:{
    email:"[email protected]"
    traveled_to: 'United States'
    someinfo:"very random"
   }
},

{  
   _id: '3'
   person:{
    email:"[email protected]"
    traveled_to: 'Russia'
    someinfo:"super super random"
   }
}

I would like for example to group [email protected] and store his info in an array

{
 _id: '1'
 person:{
  email:"[email protected]"
  travels: [
    {
      traveled_to: 'North Korea',
      someinfo:"random"
    },
    {
      traveled_to: 'United States'
      someinfo:"very random"
    }
  ]

},
{
   _id: '2'
   email:"[email protected]"
   travels:[
    {
      traveled_to: 'Russia'
      some_info:'super super random'
    }
   ]   
}

I tried something like this

People.aggregate([
    {
      $group: {
        person: {
          email: '$email',
        },
      },
    },
  ]

Although I’m getting a

MongoError: The field ‘person’ must be an accumulator object

Thanks!

Tags:

2

Answers


  1. 0

    You have to have accumulator object upon which mongoDB is grouping the values

    Try this

    People.aggregate([
    {
      $group: {
        _id: "$person.email",
        traveled_to:{
          $push:{
            traveled_to: "$person.traveled_to",
            someinfo: "$person.someinfo"
          }
        },
      },
    },
  ]
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  2. 0

    You must wrap mongoose schema using "{ }" bracket.
    like->

        People.aggregate({
     [
   {
          $group: {
            person: {
              email: '$email',
            },
          },
        },]
      }
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