Throw error when transform returns a promise

[botv]

Am I doing something wrong defining a transformer on a schema? Here's my schema code:

const bookSchema = new Schema({
  title: {
    type: String,
    transform: async function(v) {
      return await Promise.resolve(v)
    }
  },
});

When I create a new Book, I get title: {}. Do transformers have to be synchronous?

[vkarpov15]

Yes they do. JSON.stringify() is a synchronous function, so transform needs to be synchronous as well.