useMemoScoped

packages/example/package.json

@@ -35,6 +35,7 @@
     "@effect/platform-browser": "^0.52.1",
     "@radix-ui/themes": "^3.1.6",
     "@typed/id": "^0.17.1",
+    "@typed/lazy-ref": "^0.3.3",
     "lucide-react": "^0.471.1",
     "mobx": "^6.13.5"
   }

packages/example/src/routes/tests.tsx

@@ -1,5 +1,6 @@
 import { R } from "@/reffuse"
 import { createFileRoute } from "@tanstack/react-router"
+import { GetRandomValues, makeUuid4 } from "@typed/id"
 import { Console, Effect } from "effect"
 
 
@@ -12,13 +13,11 @@ function RouteComponent() {
     //     Effect.map(() => "test")
     // ))
 
-    R.useSuspenseScoped(Effect.addFinalizer(() => Console.log("cleanup")).pipe(
-        Effect.andThen(Effect.promise(() => new Promise<string>(resolve => {
-            setTimeout(() => { resolve("test") }, 0)
-        }))),
-
-        Effect.tap(Console.log),
+    const value = R.useMemoScoped(Effect.addFinalizer(() => Console.log("cleanup")).pipe(
+        Effect.andThen(makeUuid4),
+        Effect.provide(GetRandomValues.CryptoRandom),
     ), [])
+    console.log(value)
 
     return <div>Hello "/tests"!</div>
 }

packages/reffuse/src/Reffuse.ts

@@ -99,13 +99,39 @@ export class Reffuse<R> {
     ): A {
         const runSync = this.useRunSync()
 
-        const initialValue = React.useMemo(() => runSync(Effect.scoped(effect)), [])
+        // Calculate an initial version of the value so that it can be accessed during the first render
+        const [initialScope, initialValue] = React.useMemo(() => Scope.make(options?.finalizerExecutionStrategy).pipe(
+            Effect.flatMap(scope => effect.pipe(
+                Effect.provideService(Scope.Scope, scope),
+                Effect.map(value => [scope, value] as const),
+            )),
+
+            runSync,
+        ), [])
+
+        // Keep track of the state of the initial scope
+        const initialScopeClosed = React.useRef(false)
+
         const [value, setValue] = React.useState(initialValue)
 
         React.useEffect(() => {
-            const scope = runSync(Scope.make(options?.finalizerExecutionStrategy))
-            setValue(runSync(Effect.provideService(effect, Scope.Scope, scope)))
+            const closeInitialScope = Scope.close(initialScope, Exit.void).pipe(
+                Effect.andThen(Effect.sync(() => { initialScopeClosed.current = true })),
+                Effect.when(() => !initialScopeClosed.current),
+            )
 
+            const [scope, value] = closeInitialScope.pipe(
+                Effect.andThen(Scope.make(options?.finalizerExecutionStrategy).pipe(
+                    Effect.flatMap(scope => effect.pipe(
+                        Effect.provideService(Scope.Scope, scope),
+                        Effect.map(value => [scope, value] as const),
+                    ))
+                )),
+
+                runSync,
+            )
+
+            setValue(value)
             return () => { runSync(Scope.close(scope, Exit.void)) }
         }, [
             ...options?.doNotReExecuteOnRuntimeOrContextChange ? [] : [runSync],