1var str = 'On the 03/09/2015 I am swiming in a pool, that was build on the 27-03-1994';
2
3var res = str.match(/\d{2}([\/.-])\d{2}\1\d{4}/g);
4
5document.getElementById('out').value = res;

1var str = 'Test  Client wants to reschedule your call from 2021-02-18 06:30:00+00:00 to 2021-02-18T07:00';
2
3var res = str.match(/\d{2}([\/.-])\d{2}\1\d{4}/g);
4
5document.getElementById('out').value = res;