Alternative to settings menu?

I had some problem creating a settings menu for my clock. I wanted to preview different clock faces, for which i would need some functions from the clock app. Apparently, it is impossible to import functions into the settings app. My workaround was to just write a very basic settings.js:

(function(back) {
  var settings = require('Storage').readJSON("contourclock.json", true) || {};
  settings.editMode=true;
  require('Storage').writeJSON("contourclock.json", settings);
  load('contourclock.app.js');
})

The clock app just has to check for "settings.editMode", disable UI and enter its own settings mode.
Are there any problems with this approach?

One problem is you can't go back from the app settings to the settings menu.

You could maybe put the drawing code in a separate library file, like e.g. the weather app does, so you'd have something like this:

// apps/contourclock/lib.js
exports.drawClock = function(time, face) {
  // draw clockface [#face](https://forum.espruino.com/search/?q=%23face), at given time
}

// apps/contourclock/app.js
var face = Storage.readJSON('contourclock.json').face
setInterval(()=>require('contourclock').drawClock(new Date(), face), 60000);

// apps/contourclock/settings.js
(function(back) {
function preview(face) {
  require('contourclockclock').drawClock(new Date(), face);
}
// settings menu using preview() goes here
})

// apps.json
{
  "id": "contourclock"
"storage": [
      {"name":"contourclock.app.js","url":"app.js"},
      {"name":"contourclock","url":"lib.js"},
      {"name":"contourclock.settings.js","url":"settings.js"}
    ],
}

Thanks a lot! One more problem: The drawClock function needs a font module. if i put

require("FontTeletext10x18Ascii").add(Graphics);

in the main clock code, the font is loaded and works in drawClock. The same code does not work in the settings app, i get

Contour Clock settings error: Error: Error: Module FontTeletext10x18Ascii not found
Loading the font in the library does not work either, but does not produce an error message...