How to validate a date?

Question

I\'m trying to test to make sure a date is valid in the sense that if someone enters 2/30/2011 then it should be wrong.

How can I do this with any date?

Answer 1

It's unfortunate that it seems JavaScript has no simple way to validate a date string to these days. This is the simplest way I can think of to parse dates in the format "m/d/yyyy" in modern browsers (that's why it doesn't specify the radix to parseInt, since it should be 10 since ES5):

const dateValidationRegex = /^\d{1,2}\/\d{1,2}\/\d{4}$/;
function isValidDate(strDate) {
  if (!dateValidationRegex.test(strDate)) return false;
  const [m, d, y] = strDate.split('/').map(n => parseInt(n));
  return m === new Date(y, m - 1, d).getMonth() + 1;
}

['10/30/2000abc', '10/30/2000', '1/1/1900', '02/30/2000', '1/1/1/4'].forEach(d => {
  console.log(d, isValidDate(d));
});