Question: Trapping the 'Windows' key

[netaisllc]

This is only a question, but does the library effectively trap the so-called WINDOWS key?
I've used the library a lot (love it!) but this feature doesn't work for me.
Just wondering out loud....

[ccampbell]

Hey, could you be a little more specific? What keyboard command are you trying to listen for?

Mousetrap supports all the modifier keys that javascript supports on keyboard events: shift, ctrl, alt, and meta. Not sure if the windows key is one of those.

[ecgan]

Have a look here:

http://www.cambiaresearch.com/articles/15/javascript-char-codes-key-codes

Apparently the char codes for Windows keys are:

Left Window key: 91
Right Window key: 92

Code 91 corresponds to the meta key mentioned by @ccampbell , meaning the Left Window key should work. However, Right Window key (code 92) is not in mousetrap.js.

[netaisllc]

@ccampbell, @ecgan, thanks, guys.

Yes, I already inspected the char_codes purported to match the Windows key. However using a string such as 'meta+z' isn't recognized. I've also tried to mod my copy of the script to address this.

I suspect the key is not assigned 91 or 92. Craig, do you know of a technique to interrogate what codes are actually mapped to keys?

[ccampbell]

Well if the windows key doesn't map to any of the default modifier keys then it's not a simple change in mousetrap.

Mousetrap doesn't keep track of anything related to which keys are down cause that is not totally reliable. I rely on the properties on the key event object (such as e.metaKey). This means mousetrap doesn't let you do keyboard combinations such as a+b. This was a conscious decision.

To answer your question (if you want to debug) you can write a simple script such as:

document.addEventListener('keypress', function(e) {
    console.log('KEYPRESS');
    console.log('keycode', e.keyCode);
    console.log('which', e.which);
    console.log('meta', e.metaKey);
    console.log('shift', e.shiftKey);
    console.log('alt', e.altKey);
    console.log('ctrl', e.ctrlKey);
    console.log('');
}, false);

document.addEventListener('keydown', function(e) {
    console.log('KEYDOWN');
    console.log('keycode', e.keyCode);
    console.log('which', e.which);
    console.log('meta', e.metaKey);
    console.log('shift', e.shiftKey);
    console.log('alt', e.altKey);
    console.log('ctrl', e.ctrlKey);
    console.log('');
}, false);

This output would be useful to me too for the windows key.

[netaisllc]

Thanks!

I added the script to my project and did a few quick tests. The logs are attached. It certainly looks like the char codes assigned to the LeftWindows and RightWindows keys are correct.

To generate logs from the script, I had to use the Windows key in combination with another key. (Pressing the 'Windows" key alone (on Win7) displays the Start menu.) I suspect that has something to do with the results.

Lastly, I see that I failed to answer your question about my intent. I'm exploring triggering a UI change based on the Windows8 keyboard shortcuts, such as Win+Z or Win+C, in pure HTML/CSS/JS.

[ccampbell]

Unfortunately this means it is not going to be a simple thing to add to the core library since the windows key is not treated as meta, shift, ctrl, or alt.

My first recommendation would be to use a different key so it works consistently cross platform/cross keyboard layouts.

If that doesn't work you could try writing a plugin to do it. It's not the prettiest, but something like this could get you started:

var windowsKeyDown = false;
document.addEventListener('keydown', function(e) {
    if (e.keyCode == 91 || e.keyCode == 92) {
        windowsKeyDown = true; 
    }
});

document.addEventListener('keyup', function(e) {
    if (e.keyCode == 91 || e.keyCode == 92) {
        windowsKeyDown = false;
    }
});

Mousetrap.bind('z', function() {
    if (windowsKeyDown) {
        console.log('windows + z pressed');
    }
});

If the appropriate keys were referenced in the _MAP dictionary at the top of mousetrap then you could use mousetrap to listen for them.

[netaisllc]

Yeah, I actually concluded as much (and took your "first recommendation") awhile back; was just wondering if the topic had been reported/looked into. Thanks very much for your time and the library!