A webpack plugin to hot refresh for Lynx

Main Thread Functions

Rspeedy's ReactLynx HMR integration updates Main Thread Functions and their shared dependencies before refreshing the corresponding background components. This also refreshes existing event bindings when a dependency changes without changing the function's worklet ID. No additional application API is required. Application updates include already loaded async chunks and the first worklet added to a background-only module within an async scope.

Each thread loads its own versioned update bundle through Native fetchBundle and loadScript. The shared HMR loader reads a manifest section and the sections for the requested update chunks. Background sections retain the existing SDK runtime wrapper and app scope; normal lazy loading keeps its existing loader. Background bundles do not carry worklet implementations for cross-thread HMR; the compiler supplies their definitions to the main-thread bundle. A failed update on either thread, or a missing main-thread completion, triggers a full page reload. Coordinated updates allow up to ten seconds for main-thread completion, then up to ten seconds for background application. Pending updates from the old page are discarded. Compatible component updates preserve useState; memoized values, including useMainThreadRef, follow the existing Fast Refresh reset behavior.

This integration applies to application HMR and uses the host's existing Native loading and DevTool reload capabilities. It does not add standalone lazy-bundle HMR or change production bundles.

If the host lacks main-thread fetchBundle or loadScript, the coordinator disables main-thread updates and retains the existing background HMR path. Background Native loading also requires the SDK to initialize the app wrapper: hosts without these APIs or that initialization capability retain the original background loader. The manifest probes initialization before update code runs. Actual Native load or application failures still trigger a reload. These fallbacks do not add Main Thread Function HMR to hosts without main-thread loading.