Moment: isValid not works correctly

It's valid as it's been turned into a valid date:

new Date('Chicago Illinois 46702'); // Wed Jan 01 46702 00:00:00 GMT+0000 (Greenwich Mean Time)

However... you should also see a warning from moment:

moment('Chicago Illinois 46702').isValid(); 

In your JavaScript console:

Deprecation warning: value provided is not in a recognized RFC2822 or ISO format. moment construction falls back to js Date(), which is not reliable across all browsers and versions. Non RFC2822/ISO date formats are discouraged and will be removed in an upcoming major release. Please refer to http://momentjs.com/guides/#/warnings/js-date/ for more info.

How about this though

moment('22-10-2020', 'dd-MM-yyyy', true).isValid();

returns false.

EDIT
I see: moment('22-10-2020', 'DD-MM-YYYY', true).isValid(); works

const allPossibleFormats = [
  'D MMMM YYYY',
  'D MMMM YYYY HH:mm',
  'DD-MM-YY',
  'DD-MM-YYYY',
  'DD.MM.YYYY',
  'DD.MM.YYYY HH:mm',
  'DD/MM/YY',
  'DD/MM/YYYY',
  'DD/MM/YYYY HH:mm:ss',
  'HH:mm:ss',
  'M/D/YYYY',
  'D/M/YYYY',
  'MM-DD-YY',
  'MM-DD-YYYY',
  'MM-DD-YYYY HH:mm:ss',
  'MM/DD/YY',
  'MM/DD/YYYY',
  'MM/DD/YYYY HH:mm:ss',
  'MMM D YYYY',
  'MMM D YYYY LT',
  'MMMM Do YYYY',
  'MMMM Do YYYY LT',
  'YYYY-DD-MM HH:mm:ss',
  'YYYY-MM',
  'YYYY-MM-DD',
  'YYYY-MM-DD HH:mm',
  'YYYY-MM-DD HH:mm:ss',
  'YYYY-MM-DD LT',
  'YYYY-MM-DD h:mm:ss A',
  'YYYY-MM-DDTHH:mm:ssZ',
  'ddd, MMM D YYYY LT',
  'dddd D MMMM YYYY HH:mm',
  'dddd, MMMM Do YYYY LT'
];

moment('Chicago Illinois 46702', allPossibleFormats, true).isValid(); // false
moment('18/01/1944', allPossibleFormats, true).isValid(); // true
moment('22-10-2020', allPossibleFormats, true).isValid(); // true
moment('1944-01-18 12:00:00', allPossibleFormats, true).isValid(); // true
moment('2001-01-01 00:00:00', allPossibleFormats, true).isValid(); // true
moment('2001-01', allPossibleFormats, true).isValid(); // true

Also we can extend allPossibleFormats array and add another date/datetime formats

Please re-open if you still have issues.