handleKeyUp.js

handleKeyUp = (e) => {
  let shortcut = '';
  let modifiersCount = 0;

  if (e.ctrlKey) {
    shortcut += 'Ctrl ';

    modifiersCount++;
  }

  if (e.metaKey) {
    shortcut += 'Command ';

    modifiersCount++;
  }

  if (e.shiftKey) {
    shortcut += 'Shift ';

    modifiersCount++;
  }

  if (e.altKey) {
    shortcut += 'Alt ';

    modifiersCount++;
  }

  shortcut += e.key;

  shortcut = shortcut.split(' ').join('+');

  if (modifiersCount === 0 || modifiersCount > 2) return;

  if (e.keyCode < 65 || e.keyCode > 90) return;

  console.log('valid shortcut');
};