isValid = false;
while (isValid == false) {
let night = Number(window.prompt("pick a night"));
if (typeof night == 'number' && night >= 1 && night <= 8) {
isValid = true;
}
}
document.write(night); //not accessibleYou must define variable night outside of the while loop, like this:
[...]
let night
let isValid = false;
while(isValid == false) {
night = Number(window.prompt("pick a night"));
if(typeof night == 'number' && night >= 1 && night <= 8){
isValid = true;
}
}
document.write(night);
[...]
let is a block scope variable i.e. it will only be accessible in the while loop. If you want to access it outside the while loop, declare it as a var variable which is a global scope.
To be honest, I wouldn't even recommend using a while loop.
Also, one issue with your code is that you are checking if typeof night === 'number', but it will always be number since you wrapped the value in Number(). NaN itself is of the number type.
<script>
const getNight = () => {
const night = +window.prompt('Pick a night:');
if (isNaN(night) || night < 1 || night > 8) {
alert('Try again.');
return getNight();
}
return night;
};
document.write(getNight());
</script>