Background

JSAR Runtime currently lacks a unified input event management system and does not support DOM Keyboard Events such as keydown and keyup. For extensibility and cross-platform compatibility, input event capture should be abstracted away from the core runtime and handled by the integrating application.

Proposal

• InputManager Module
  • Add a new module in src/runtime (e.g. src/runtime/input-manager) responsible for managing input events (keyboard, mouse, etc.).
  • InputManager should NOT directly listen to system events. Instead, it provides an interface for the host/integrated application to forward input events to JSAR Runtime. This allows different platforms (Unity, Unreal, native, etc.) to implement their own input event listeners and inject events into JSAR.
  • InputManager receives input events (e.g. keyboard) from the host application and broadcasts them through the existing IPC mechanism to the correct JSAR application instance.
  • On the client side, these events are mapped to standard DOM events (such as KeyboardEvent) and dispatched to the appropriate DOM nodes.
• KeyboardEvent API
  • Implement standard DOM KeyboardEvent support on the client side, including bubbling, capture, and cancellation (preventDefault).
  • Ensure compatibility with addEventListener and related DOM APIs.

Benefits

• Clean separation between event capture and event management, increasing portability and modularity.
• Enables robust keyboard input support, improving accessibility and usability for JSAR-powered apps.
• Host applications retain control over platform-specific input integration.

References

• MDN KeyboardEvent
• Input event handling in game engines (Unity, Unreal, etc.)

Acceptance Criteria

• InputManager module exists in src/runtime and exposes APIs for host applications to inject input events.
• Keyboard events are correctly dispatched from InputManager to client DOM as standard events.
• Example/demo provided for host-side event injection and DOM event handling.
• Integration guide/documentation updated to describe platform-specific input event forwarding.