Answer by LocV's Nest for Detecting an "invalid date" Date instance in JavaScript

Maybe I'm late but I have a solution.

const isInvalidDate = (dateString) => JSON.stringify(new Date(dateString)) === 'null';const invalidDate = new Date('Hello');console.log(isInvalidDate(invalidDate)); //trueconst validDate = new Date('2021/02/08');console.log(isInvalidDate(validDate)); //false