Currently we have multiple date formats in our database:

DD/MM/YYYY
DD-MM-YYYY
YYYY/MM/DD
YYYY-MM-DD

We all want to format these to one format YYYY-MM-DD. When using dayjs to do this I'm getting NaN-NaN-NaN back when running dayjs('14/05/1993').format('YYYY-MM-DD')

We can add a format to dayjs by adding the customParseFormat plugin

dayjs.extend(customParseFormat)
dayjs('14/05/1993', 'DD/MM/YYYY').format('YYYY-MM-DD')

But how can we detect the format for all four formats we have?

(Solution may be without dayjs)

CodePudding user response：

String Format

If you know the format of an input string, you can use that to parse a date.

This dependent on CustomParseFormat plugin to work

dayjs.extend(customParseFormat) dayjs("12-25-1995", "MM-DD-YYYY")

Pass the locale key as the third parameter to parse locale-aware date time string.

require('dayjs/locale/es') dayjs('2018 Enero 15', 'YYYY MMMM DD', 'es')

You may specify a boolean for the last argument to use strict parsing. Strict parsing requires that the format and input match exactly, including delimiters.

dayjs('1970-00-00', 'YYYY-MM-DD').isValid() // true
dayjs('1970-00-00', 'YYYY-MM-DD', true).isValid() // false
dayjs('1970-00-00', 'YYYY-MM-DD', 'es', true).isValid() // false

If you don't know the exact format of an input string, but know it could be one of many, you can use an array of formats.

dayjs("12-25-2001", ["YYYY", "YYYY-MM-DD"], 'es', true);

Source: https://day.js.org/docs/en/parse/string-format

With that...

const possibleDateFormats = ["DD/MM/YYYY", "DD-MM-YYYY", "YYYY/MM/DD", "YYYY-MM-DD"];

dayjs('14/05/1993', possibleDateFormats).format('YYYY-MM-DD');

CodePudding user response：

This should solve your problem as long as your date format is consistent

function dateFormatter(dateString) {
      
      if (dateString.includes('-')) {
            const splittedDate = dateString.split('-');
            if (splittedDate[2].length === 4) {
                 return splittedDate.reverse().join('-')
            }
            else {
                  return splittedDate.join('-')
            }


      } else {
            const splittedDate = dateString.split('/');
            if (splittedDate[2].length === 4) {
                 return splittedDate.reverse().join('-')
            }
            else {
                  return splittedDate.join('-')
            }
      }

}


console.log(dateFormatter('2020/15/5'))