Mongoose中的条件子文档

Question

我想在Mongoose模型中有一个条件SubDocument。

在下面的代码中，我尝试传达我想要做的事情。

var SubSchemaA = new Schema({
  address: { type:String, required:true }
});

var SubSchemaB = new Schema({
  birthday: { type:Date, required:true }
});

var MainSchema = new Schema({
  type: String, enum: ['A', 'B'],
  content: Schema, enum: [SubSchemaA, SubSchemaB]
});

MainSchema.pre('validate', function (next) {
  var content = this.content;

  if (this.type == 'A') {
    this.content = SubSchemaA(content)
  } else {
    this.content = SubSchemaB(content)
  }
  next()
});