code: function getKeyStrokeString(ev) {
      var keys = [];
  
      if (ev.ctrlKey || ev.metaKey) {
          keys.push('ctrl');
      }
      if (ev.shiftKey) {
          keys.push('shift');
      }
      keys.push(keyNameMap[ev.keyCode]);
  
      return keys.join('-');
  }
docs: Returns the keyStroke string
  @param {Event} ev - Keyboard event
  @returns {String}
  @ignore