mongoose填充字段没有参考选项

我有3个模式:

var User1Schema = new Schema({ name: {type:String , trim: true, required: true }, status: {type:Number, required: true, default:1} },{collection:"user_1"}); 

 var User2Schema = new Schema({ name: {type:String , trim: true, required: true }, email: {type: String, required: true, index: {unique: true} }, status: {type:Number, required: true, default:1} },{collection:"user_2"}); 

 var ConversationSchema = new Schema( { participants: [{user:{type: ObjectId, required: true}], creator: {type: ObjectId, required: true}, status: { type:Number, required: true, default:1 } }, { collection:"conversation" } ); 

在ConversationSchema中,我有创build者字段,现在有ref选项,因为它可以是User1Schema或User2Schematypes。

我如何使用mongoose填充创build者字段

 Conversation.find().populate('creator', null, 'User2').exec(callback) 

文件不清楚。 将尽快更新。

另外,这个语法在v3.6中会更简单。