小程序日期加减封装函数

1，utils下新建dateCount.js

     function addDay(start_time, addday) {
       if (!(start_time instanceof Date)) {
           start_time = new Date(start_time);
       }
       var newday = start_time.getTime() + addday * 24 * 60 * 60 * 1000;
       newday = new Date(newday);
       // return newday.toLocaleDateString()
       var d = newday;
       var ye = d.getFullYear();
       var mo = (d.getMonth() + 1).toString().padStart(2, '0');
       var da = d.getDate().toString().padStart(2, '0');
       var time = ye + '-' + mo + '-' + da;
       return time; 
       }
  
   
   

function minusDay(end_time, minusday) {
       if (!(end_time instanceof Date)) {
           end_time = new Date(end_time);
       }
       var newday = end_time.getTime() - minusday * 24 * 60 * 60 * 1000;
       newday = new Date(newday);
       // return newday.toLocaleDateString()
       var d = newday;
       var ye = d.getFullYear();
       var mo = (d.getMonth() + 1).toString().padStart(2, '0');
       var da = d.getDate().toString().padStart(2, '0');
       var time = ye + '-' + mo + '-' + da;
       return time;
   }
    module.exports = {
       addDay,
       minusDay
   }

2，使用页面引入

import dateCount from '../../utils/dateCount'

3，调用接收

let addDate = dateCount.addDay(date, 1) 第一个参数为当前日期，第二个参数为加减几天