is-date-invalid.ts
function isDateInvalid(date: Date): boolean {
  return Number.isNaN(date.valueOf());
}

The new Date() constructor will not throw an error if you pass it a wrong value, checking the value of the returned date object is the only way to know if the date is invalid.

isDateInvalid(new Date()) // false
isDateInvalid(new Date('2023-55-99')) // true
is-date-invalid.ts
function isDateInvalid(date: Date): boolean {
  return Number.isNaN(date.valueOf());
}

The new Date() constructor will not throw an error if you pass it a wrong value, checking the value of the returned date object is the only way to know if the date is invalid.

isDateInvalid(new Date()) // false
isDateInvalid(new Date('2023-55-99')) // true