检查日期是否已经用时刻解析

Question

I am passing down a date string which needs to be parsed appropriately with moment . The problem is in some circumstances it is getting parsed twice, which causes it to become undefined .

this is what the code currently looks like:

moment.tz(dt, 'MMMM D, YYYY', timezone).toDate()

When I parse it the second time, I get:

moment.invalid(/* 2018-09-21T05:00:00.000Z */)

Which causes when I do toDate() to become undefined .

while the first time I will get exactly what I expect:

'2019-02-01T05:00:00.000Z'

Before doing any of this I would like to check if it already if in the format I expect it to be. How do I do this?

Answer 1

You could potentially use the isValid() method to check if the parsing worked before calling toDate() . Demo:

 var timezone = "America/Los_Angeles"; var dt = 'Sept 21, 2018'; var m = moment.tz(dt, 'MMMM D, YYYY', timezone); var converted = m.toDate().toString(); console.log(converted); var x = moment.tz(converted, 'MMMM D, YYYY', timezone); console.log(x.isValid()); //if parsing worked, use the new value if (x.isValid()) { console.log(x.toDate()); } // if not, assume it's already the correct format and just use that else { console.log(converted); }

 <script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.22.2/moment.min.js"></script> <script src="https://cdnjs.cloudflare.com/ajax/libs/moment-timezone/0.5.21/moment-timezone-with-data.min.js"></script>