不正确的日期格式 moment.js

Question

I have an input with the following date inside my util function (the first argument) - '2013-12-15'. I use the format 'MM/DD/YYYY' as a second argument for the format moment.js method. Actual result: 12/14/2013 instead of 12/15/2013 (input date equals to '2013-12-15'). The question is - why moment subtract one day after formatting?

export const formatDateTime = (date, format = MM/DD/YYYY) => {
    let useFormat = format

    return moment
        .utc(date)
        .tz('America/New_York')
        .format(useFormat)
} // return '12/14/2013'

Answer 1

I don't know the reason for reducing a day, but one way you can do to format the date would be using regular expression like this:

 const formatDate = date => { let regX = /(\d+)\/(\d+)\/(\d+)/ // AAAA-MM-DD return date.replace(regX, '$2/$3/$1') }

Answer 2

You're providing a timezone for moment. Moment will create a Date object and the date is going to be something like 2013-12-15T00:00:00Z , then moment will apply timezone, thus date will become 2013-12-14T18:00:00Z . This is not 100% corrent