I have added a transform function to my Schema's `toObject` to strip certain properties, and change the name of `_id` to `id`. It works great when I use `findOne` and call `toObject` on the result, but I also have a `find({}, (err, items) => {...})` command. There's no way to call `toObject` on the array.

Here's my schema:

```
var ItemSchema = new Schema({
    version: {type: String, default: '1.0.0'},
    created: {type: Date, default: Date.now},
    modified: {type: Date, default: Date.now},
    properties: Schema.Types.Mixed
  }, {
  toObject: {
    transform: (doc, ret) => {
      // remove the _id and __v of every document before returning the result
      ret.id = doc.id;
      delete ret._id;
      delete ret.__v;
    }
  }
});

```

I've looked it up, and could only find [this question](https://stackoverflow.com/questions/17795219/transform-an-array-of-documents-using-mongoose?s=2%7C1.2601), where the recommended answer is to use `lean()` - which does not help me.

As a workaround, I added the line `var result = items.map(x => x.toObject());`, and while it works great, I wonder if there's a way to trigger the transform automatically on any document returned - single or array, so I won't have to iterate over the results.