export function manifestShortcutKey()

in src/schema/formats.js [84:145]
46 lines of code
12 McCabe index (conditional complexity)

export function manifestShortcutKey(value) {
  // Partially taken from Firefox directly via
  // https://searchfox.org/mozilla-central/source/toolkit/components/extensions/Schemas.jsm#987
  // Please make sure to always update this function when doing a schema update
  // to pull in the most recent implementation to stay up-to-date with upstream.

  const MEDIA_KEYS =
    /^(MediaNextTrack|MediaPlayPause|MediaPrevTrack|MediaStop)$/;
  const BASIC_KEYS =
    /^([A-Z0-9]|Comma|Period|Home|End|PageUp|PageDown|Space|Insert|Delete|Up|Down|Left|Right)$/;
  const FUNCTION_KEYS = /^(F[1-9]|F1[0-2])$/;

  if (MEDIA_KEYS.test(value.trim())) {
    return true;
  }

  const modifiers = value.split('+').map((s) => s.trim());
  const key = modifiers.pop();

  if (!BASIC_KEYS.test(key) && !FUNCTION_KEYS.test(key)) {
    return false;
  }

  const chromeModifierKeyMap = {
    Alt: 'alt',
    Command: 'accel',
    Ctrl: 'accel',
    MacCtrl: 'control',
    Shift: 'shift',
  };

  const chromeModifiers = modifiers.map((m) => chromeModifierKeyMap[m]);

  // If the modifier wasn't found it will be undefined.
  if (chromeModifiers.some((modifier) => !modifier)) {
    return false;
  }

  switch (modifiers.length) {
    case 0:
      // A lack of modifiers is only allowed with function keys.
      if (!FUNCTION_KEYS.test(key)) {
        return false;
      }
      break;
    case 1:
      // Shift is only allowed on its own with function keys.
      if (chromeModifiers[0] === 'shift' && !FUNCTION_KEYS.test(key)) {
        return false;
      }
      break;
    case 2:
      if (chromeModifiers[0] === chromeModifiers[1]) {
        return false;
      }
      break;
    default:
      return false;
  }

  return true;
}