indexes not being added for array fields

If I have some schema defined like this:

schema = new Schema({_some_array_field: [{type: String, index: true}]})

There’s no index on _some_array_field if I check with getIndexes() from the shell.

I need to explicitly do schema.index({_some_array_field: 1})

UPDATE: It looks like if I specify the array field like this, the index gets applied:

schema = new Schema({_some_array_field: {type: [String], index: true}})

So it seems to be relating to how the index options are being parsed out.

[wavded]

this seems to work:

 properties : { type: [{ type: ObjectId, ref: 'Property' }], index: true },

[aheckmann]

this is by design as you have discovered.