Check if a user input is NaN

Question

I am trying to write a small program, and I have 3 conditions for the program to proceed.

1. prompt user input again if hour > 12
2. prompt user input again if hour < 1
3. prompt user input again if hour === NaN (I am stuck with the 3rd condition)

Here is the code I wrote to cope with 1st 2 conditions and unable to do the 3rd.

let hour = parseInt(prompt('Enter Hour'));

while (hour > 12 || hour < 1) {
    hour = parseInt(prompt('Enter Valid Hour'));
}

i am pretty new to coding. Help is appreciated.

Answer 1

let hour = parseInt(prompt('Enter Hour'));

while (hour > 12 || hour < 1 || isNaN(hour)) {
    hour = parseInt(prompt('Enter Valid Hour'));
}

Answer 2

You need to use isNaN()

let hour = parseInt(prompt('Enter Hour'));

while (hour > 12 || hour < 1 || isNaN(hour)) {
    hour = parseInt(prompt('Enter Valid Hour'));
}