Exokit
Native VR/AR/XR engine for JavaScript
... (especially) if they aren't designed to cooperate. Apps should run in "reality tabs", layers of reality that blend together. Exokit is a Javascript Node.js module. C++ bindings hook into WebGL, WebXR, Magic Leap, Leap Motion, and various other device APIs. Exokit runs on Windows, macOS, Linux (x64), Linux (ARM64), and Magic Leap (ARM64).