How can I test a variable to ascertain if it contains a number, and it is an integer?
e.g.
if (1.589 == integer) // false
if (2 == integer) // true
Any clues?
num % 1 === 0
This will convert num to type Number first, so any value which can be converted to an integer will pass the test (e.g. '42', true).
If you want to exclude these, additionally check for
typeof num === 'number'
You could also use parseInt() to do this, ie
parseInt(num) == num
for an untyped check and
parseInt(num) === num
for a typed check.
Note that the tests are not equivalent: Checking via parseInt() will first convert to String, so eg true won't pass the check.
Also note that the untyped check via parseInt() will handle hexadecimal strings correctly, but will fail for octals (ie numeric strings with leading zero) as these are recognized by parseInt() but not by Number(). If you need to handle decimal strings with leading zeros, you'll have to specify the radix argument.
