js 字符串中固定位置插入字符

场景：后端返回时间为20220329151231
需要的格式为 2022-03-29 15:12:31

// 20220329151231
var newDate = '';
if (date) {
	var arrDate = date.split('');
	arrDate[4] = "-" + arrDate[4];
	arrDate[6] = "-" + arrDate[6];
	arrDate[8] = " " + arrDate[8];
	arrDate[10] = ":" + arrDate[10];
	arrDate[12] = ":" + arrDate[12];
	var newStr = arrDate.join().replace(/,/g, "");
	newDate = newStr;
}
// 2022-03-29 15:12:31