查询使用mongoose中的正则表达式搜索对象数组

I have my schema like below:

我的架构如下:

var QuestionListSchema = newSchema({
    topics: [{
        _id: false,
        topicID: Number,
        topicName: String,
        quesList: [{
            quesListID: Number,
            quesListName: String,
            _id: false,
            by: String,
            questions: [{
                questionId: Number,
                _id: false,
                question: String
            }]
        }]
    }]
});
var Qu