SchemaArrayOptions looks emptier than other schema options

[NebSehemvi]

Do you want to request a feature or report a bug?

Looks like a bug, might be a feature.

What is the current behavior?

After creating some schemas, like this

const Question = new mongoose.Schema({
  category: { name: 'Category', type: mongoose.Types.ObjectId, ref: 'QuestionCategory', required: true },
  likes: [{ name: 'Liked by', type: mongoose.Types.ObjectId, ref: 'User' }],
  tags:  [{ type: String, name: 'Tags' }],
});

I wanted to write a function which gets schema in JSON for frontend with +1 level deep with ref for ObjectId & ObjectId[] document properties, but there's no ref property in array options.

And this is what I get (I've omitted _id & __v in my func):

{
  category: ObjectId {
    path: 'category',
    instance: 'ObjectID',
    validators: [ [Object] ],
    getters: [],
    setters: [],
    options: SchemaObjectIdOptions {
      name: 'Category',
      type: [Function],
      ref: 'QuestionType',
      required: true
    },
    _index: null,
    isRequired: true,
    requiredValidator: [Function (anonymous)],
    originalRequiredValue: true,
    [Symbol(mongoose#schemaType)]: true
  },
  likes: SchemaArray {
    schemaOptions: {
      typeKey: 'type',
      id: true,
      noVirtualId: false,
      _id: true,
      noId: false,
      validateBeforeSave: true,
      read: null,
      shardKey: null,
      autoIndex: null,
      minimize: true,
      discriminatorKey: '__t',
      versionKey: '__v',
      capped: false,
      bufferCommands: true,
      strict: true,
      pluralization: true
    },
    casterConstructor: [Function: ObjectId] {
      schemaName: 'ObjectId',
      get: [Function (anonymous)],
      _checkRequired: [Function (anonymous)],
      _cast: [Function: castObjectId],
      cast: [Function: cast],
      checkRequired: [Function (anonymous)]
    },
    caster: ObjectId {
      path: 'likes',
      instance: 'ObjectID',
      validators: [],
      getters: [],
      setters: [],
      options: [SchemaObjectIdOptions],
      _index: null,
      [Symbol(mongoose#schemaType)]: true
    },
    '$isMongooseArray': true,
    path: 'likes',
    instance: 'Array',
    validators: [],
    getters: [],
    setters: [],
    options: SchemaArrayOptions { type: [Array] },
    _index: null,
    defaultValue: [Function: defaultFn] { '$runBeforeSetters': true },
    [Symbol(mongoose#schemaType)]: true
  },
  tags: SchemaArray {
    schemaOptions: {
      typeKey: 'type',
      id: true,
      noVirtualId: false,
      _id: true,
      noId: false,
      validateBeforeSave: true,
      read: null,
      shardKey: null,
      autoIndex: null,
      minimize: true,
      discriminatorKey: '__t',
      versionKey: '__v',
      capped: false,
      bufferCommands: true,
      strict: true,
      pluralization: true
    },
    casterConstructor: [Function: SchemaString] {
      schemaName: 'String',
      _cast: [Function: castString],
      cast: [Function: cast],
      get: [Function (anonymous)],
      _checkRequired: [Function (anonymous)],
      checkRequired: [Function (anonymous)]
    },
    caster: SchemaString {
      enumValues: [],
      regExp: null,
      path: 'tags',
      instance: 'String',
      validators: [],
      getters: [],
      setters: [],
      options: [SchemaStringOptions],
      _index: null,
      [Symbol(mongoose#schemaType)]: true
    },
    '$isMongooseArray': true,
    path: 'tags',
    instance: 'Array',
    validators: [],
    getters: [],
    setters: [],
    options: SchemaArrayOptions { type: [Array] },
    _index: null,
    defaultValue: [Function: defaultFn] { '$runBeforeSetters': true },
    [Symbol(mongoose#schemaType)]: true
  }
}

What is the expected behavior?

tags.options must contain custom attribute 'name' with value 'Tags'
likes.options must contain custom attribute 'name' with value 'Liked by' and ref attirubte with corresponded ref

I guess it can be fixed in lib\schema\array.js; in some point of function lifecycle there's ref on cast and options, but then it gets omitted.

What are the versions of Node.js, Mongoose and MongoDB you are using? Note that "latest" is not a version.
node: v13.1.0
mongod: v4.2.1
mongoose: v5.7.13

[vkarpov15]

The issue here is that ref isn't an option on the array schematype, it's an option on the ObjectId schematype within the array. For example, if you print out schema.path('likes.$').options, you'll see ref there. We'll add an $embeddedSchemaType property on arrays that lets you easily reference the underlying schematype, but as a workaround you can just use schema.path('likes.$')

See Schema#path() docs.

[horvbalint]

Hi @vkarpov15!
I know this is an old issue, but this is the only one I found mentioning the $embeddedSchemaType field. I too want to get the embedded type of an array, but sadly $embeddedSchemaType is not part of the SchemaType typescript interface.
Is this a bug, shold I open an issue for it?

[vkarpov15]

@horvbalint out of curiousity, why not just get the array's embedded type using schema.path('likes.$') as suggested?

[horvbalint]

@vkarpov15 I am, thanks to your previous answer, but its meaning is not self-explanatory at first glance and it also means I have to pass the schema to my "processField" function to get the field's embedded type. Both of which would be better with $embeddedSchemaType 😄
It's not a huge problem,just ergonomics :)