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mongodbmongoosegraphqlaggregation-frameworkapollo-server
Mike Will
Mike Will

Reputation: 309

Graphql returns null id for mongoose aggregation query

Graphql returns null id for mongoose aggregation query, but works ok other mongoose queries.

Here is my mongoose schema:

const { Schema } = mongoose;
const ObjectId = Schema.Types.ObjectId;

const productSchema = new Schema({
  _id: ObjectId,
  price: Number
})

const Product = mongoose.model('Product', productSchema, 'Product')

Here is my Graphql schema:

type Product {
    id: ID
    price: String
}

Graphql normal query:

   context.Product.findOne()

Result with console.log:

[ {
    price: 10,    
    _id: 5d7f8efebff791dcd3bb1b69
}]

Result with graphql:

 "getSearch": [
      {
        "id": "5d7f8efebff791dcd3bb1b69",
        "price": 10,
  }]

Everything is fine here. Now the problem is with aggregation query:

GraphQL query:

context.Product.aggregate(
          [
            { $sample: { size: 1 } }
          ]
    )

Result with console.log:

[ { _id: 5d7f8f23bff791dcd3bb1da3,
    price: 5
}]

Result with GraphQL:

 "test": [
          {
            "id": null",
            "price": 7,
      }]

The problem here is:

Upvotes: 5

Views: 1845

Answers (4)

Abdulkadir Ugas
Abdulkadir Ugas

Reputation: 501

Adding id element to the result works fine to mine

   const res = await Product.aggregate(
          [
            { $sample: { size: 1 } }
          ]
    )
    res.forEach(element => {
         element.id = element._id 
    });
    return res;

Upvotes: 1

Vinci
Vinci

Reputation: 1286

If you are using mongoose with nest js and GraphQL, I have fixed it by changing the id to _id and removing the @prop above it Example on github

  @Prop()//remove this
  @Field(() => ID,{ nullable: true })
  _id: string;

Upvotes: 0

semperlabs
semperlabs

Reputation: 458

Just add both IDs if you don't want to change every single instance of it.

type Product {
  id: ID
  _id: ID
  price: String
}

Upvotes: 0

Daniel Rearden
Daniel Rearden

Reputation: 84657

Documents in MongoDB normally don't have an id property, just an _id property. This is shown in the console output you're seeing. However, mongoose model instances do have a getter for id that returns the value of id. From the docs:

Mongoose assigns each of your schemas an id virtual getter by default which returns the documents _id field cast to a string, or in the case of ObjectIds, its hexString.

What's returned by methods like find and findOne are instances of the Model that have this getter. However, using aggregate results in plain JavaScript objects being returned instead (with no getter).

You can write a resolver for the id field to pull the value from either id or _id:

function resolve (parent, args, context, info) {
  return parent.id || parent._id
}

Upvotes: 4

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