js把字符串(yyyymmdd)转换成日期格式（yyyy/mm/dd）

var questionNumberTime1='20220608';

方法一：

​​var​​ ​​r=​​​​questionNumberTime1​​​​.replace(/^(\d{4})(\d{2})(\d{2})$/, ​​​​"$1/$2/$3"​​​​)​​

方法二：

​​var​​​ ​​pattern = /(\d{4})(\d{2})(\d{2})/;​​

​​var​​ ​​formatedDate = questionNumberTime1.replace(pattern, ​​​​'$1/$2/$3'​​​​)​​

方法三：

var questionNumberTime='Q20220608';

var questionNumberTime1 = questionNumberTime.replace(/Q/g, "").split("")

 questionNumberTime1.splice(4, 0, "/")

       questionNumberTime1.splice(7, 0, "/")

       var newquestionNumberTime = new Date(questionNumberTime1.join(""))