Question

I’m trying to manage my if statements into a switch statement to evaluate regex, but I don’t know how I can go about it. I tried many possibilities but cannot do it. See code below, is it right?:

var username = $('input.username'),
    phone = $('input.phone'),
    numRegex = /^[0-9]/i,
    alphaRegex = /^[a-zA-Z]/i,
    usernameVal = username.val(),
    phoneVal = phone.val();

switch (phoneVal) {

  case numRegex.test(phoneVal):
    console.log('Only digits please.');
    break;

  default:
    console.log('It\'s all good.');

}

Many thanks.

Answer 1

I think this kind of defeats the point of the switch statement having the conditions in the case statements. It’s intent is to test multiple outputs given a single input.

Perhaps if JavaScript supported multiple inputs (or destructuring of arrays) in a switch..case I could see something like this:

switch (numRegex.test(phoneVal), alphaRegex.test(usernameVal)) {
    case false, false:
        console.log('Neither are valid.');
        break;

    case true, false:
        console.log('Invalid username.');
        break;

    /* snip */

    default:
        console.log('All\'s good.');
}

But alas, I’d say sticking with if..else is a better and easier to follow/understand option, in this case:

if (numRegex.test(phoneVal)) {
    console.log('Only digits please.');
    return false;
} else if (alphaRegex.test(usernameVal)) {
    console.log('Only alpha-numeric please.');
    return false;
} else {
    console.log('It\'s all good.');
    return true;
}