You can use moment to parse date strings.
By default moment tries to parse the date as an ISO-8601 string and if that does not work falls back to the browsers new Date(). Since the way that browsers construct dates varies it is best to try not to fall back to this.
moment('2016-02-04').format('YYYY-MM-DD')
// ->'2016-02-04'
If you have a format other then ISO 8601 it is best to pass the format string as a second argument to moment.
moment('04-02-2016', 'MM-DD-YYYY').format('YYYY-MM-DD')
// ->'2016-02-04'