const date1 = new Date(fieldsValue.examStartTime);
const date2 = new Date(fieldsValue.examEndTime);
const s1 = date1.getTime();
const s2 = date2.getTime();
const Minute2 = Number((s2 - s1) / 60000);
const Minute1 = Number(fieldsValue.duration)
js日期相减得到分钟数
原文地址：https://www.cnblogs.com/chen-cheng/p/10399989.html