Vue中watch监听对象子属性

参考：

https://blog.csdn.net/qq_41818857/article/details/106621245

Vue中watch监听对象属性要加引号

watch: {

    'subjectInfo.subjectType'(val){

        if(val === magicNum.DUOXUAN){

            this.subjectInfo.answer = []

        }else{

            this.subjectInfo.answer = ''

        }

    }

},