working scroll restoration

Author: birkskyum

packages/solid-router/src/Transitioner.tsx

@@ -36,14 +36,19 @@ export function Transitioner() {
   const previousIsPagePending = usePrevious(isPagePending)
 
   router.startTransition = (fn: () => void | Promise<void>) => {
-    setIsTransitioning(true)
-    Solid.startTransition(async () => {
-      try {
-        await fn()
-      } finally {
-        setIsTransitioning(false)
-      }
+    // Execute fn synchronously to check if it returns a Promise
+    let result: void | Promise<void>
+    Solid.startTransition(() => {
+      result = fn()
     })
+
+    // If fn returned a Promise, track the transition state
+    if (result! instanceof Promise) {
+      setIsTransitioning(true)
+      result.finally(() => {
+        setIsTransitioning(false)
+      })
+    }
   }
 
   // Subscribe to location changes