Method isPrintableCharacter

lib/input-handler.ts:285–294

* Check if this is a printable character with no special modifiers * @param event - KeyboardEvent * @returns true if printable character

(event: KeyboardEvent)

   * @returns true if printable character
   */
  private isPrintableCharacter(event: KeyboardEvent): boolean {
    // If Ctrl, Alt, or Meta (Cmd on Mac) is pressed, it's not a simple printable character
    // Exception: AltGr (Ctrl+Alt on some keyboards) can produce printable characters
    if (event.ctrlKey && !event.altKey) return false;
    if (event.altKey && !event.ctrlKey) return false;
    if (event.metaKey) return false; // Cmd key on Mac

    // If key produces a single printable character
    return event.key.length === 1;
  }

  /**
   * Handle keydown event