验证日期格式正则表达式

function myFunction(){
  
//yyyy-mm-dd hh:mm:ss
    var reDateTime =/^(?:19|20)[0-9][0-9]-(?:(?:0[1-9])|(?:1[0-2]))-(?:(?:[0-2] 
   [1-9])|(?:[1-3][0-1])) (?:(?:[0-2][0-3])|(?:[0-1][0-9])):[0-5][0-9]$/;
//yyyy-mm-dd hh:mm
var reDateTime =/^(?:19|20)[0-9][0-9]-(?:(?:0[1-9])|(?:1[0-2]))-(?:(?:[0-2] 
   [1-9])|(?:[1-3][0-1])) (?:(?:[0-2][0-3])|(?:[0-1][0-9]))$/;
    var isDateTime = reDateTime.test('2020-05-14 08:30');
     
    alert(isDateTime);
}