JQuery, check for arrow key pressed swith statement

Question

I've setup a keydown function and I want to do different things depending on whether the left, right, up or down arrow keys are pressed. That's working using a switch statement, but I'd also like to do something when ANY arrow key is pressed, but can't figure it out. My code:

$(document).keydown(function (e) {

var keyCode = e.keyCode || e.which,
    arrow = {left: 37, up: 38, right: 39, down: 40 },

switch (keyCode) {

    case arrow.left:
        // do something left
    break;

    case arrow.right:
        // do something right
    break;
}       

}); 

I would really just like a line of code where I could check for whether any arrow key is pressed, but can't figure it out, so for example:

case arrow:
    // do something for any arrow keys
break;

Just using "case arrow doesn't seem to work. Could anyone help?

Thanks in advance!

EDIT: Thanks for your help everyone. Here's my final code, for anyone looking:

$(document).keydown(function (e) {

    if (e.which >= 37 && e.which <= 40) {
        $('p.key-notification').fadeOut('slow');
    }

    var keyCode = e.keyCode || e.which,
    arrow = {left: 37, up: 38, right: 39, down: 40 },

    switch (keyCode) {

        case arrow.left:
            // do something left
        break;

        case arrow.right:
            // do something right
        break;
    }       

}); 

Answer 1

Why does that also have to be within your switch statement?

Make a separate if statement after your switch:

if (keyCode >= 37 && keyCode <= 40) {
    // run your code here
}

Answer 2

A single switch statement isn't able to match on multiple conditions - you can have fall-through, but that doesn't evaluate the expression on subsequent cases and won't achieve your desired effect. I'd do it like this:

if (keyCode >= 37 && keyCode <= 40) {
   // do any processing for _any_ arrow key here if it should happen
   // before individual arrow key processing

   switch (keyCode) {

      case arrow.left:
        // do something left
        break;

      case arrow.right:
        // do something right
        break;
   }

   // do any processing for _any_ arrow key here if it should happen
   // after individual key processing
}

Putting the switch inside the if statement saves evaluating it when none of the cases would've matched. (So obviously if you later wanted the switch to handle other keys you'd need to move it out of the if.)

If you needed to do something similar for keys that didn't have consecutive key codes then obviously you couldn't use a >= && <= condition so you'd do something like this:

if (keyCode === arrow.left || keyCode === arrow.right
   || keyCode === arrow.up || keyCode === arrow.down) {

Answer 3

This should work for you needs if I understand you correctly.

Another approach that adds to readability

var  arrow = { left: 37, up: 38, right: 39, down: 40 };

Any of them

switch (evt.keyCode) {
    case arrow.right:
    case arrow.left:
    case arrow.up:
    case arrow.down:
        // Do something
        break;
}

One of

switch (evt.keyCode) {
    case arrow.right:
        // Do right
        break;
    case arrow.left:
        // Do left
        break;
    case arrow.up:
        // Do up
        break;
    case arrow.down:
        // Do down
        break;
}