From 95f53b8a009c5e89fff95fdce98cd0ac623b02f2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Julien=20Valverd=C3=A9?= <julien.valverde@mailo.com>
Date: Thu, 30 Oct 2025 11:58:06 +0100
Subject: [PATCH] Add useOnMountResult

---
 packages/effect-fc/src/Component.ts | 31 ++++++++++++++++++++++++++---
 1 file changed, 28 insertions(+), 3 deletions(-)

diff --git a/packages/effect-fc/src/Component.ts b/packages/effect-fc/src/Component.ts
index c2823b8..ed24655 100644
--- a/packages/effect-fc/src/Component.ts
+++ b/packages/effect-fc/src/Component.ts
@@ -514,13 +514,38 @@ export const useOnChange: {
     ), [scope])
 })
 
-export namespace useOnChangeResult {
-    export interface Options<A, E, P>
-    extends Result.forkEffectScoped.Options<P>, useReactEffect.Options {
+export namespace useOnMountResult {
+    export interface Options<A, E, P> extends Result.forkEffectScoped.Options<P> {
         readonly equivalence?: Equivalence.Equivalence<Result.Result<A, E, P>>
     }
 }
 
+export const useOnMountResult: {
+    <A, E, R, P = never>(
+        f: () => Effect.Effect<A, E, Result.forkEffectScoped.InputContext<R, NoInfer<P>>>,
+        options?: useOnChangeResult.Options<A, E, P>,
+    ): Effect.Effect<Result.Result<A, E, P>, never, Result.forkEffectScoped.OutputContext<R>>
+} = Effect.fnUntraced(function* <A, E, R, P = never>(
+    f: () => Effect.Effect<A, E, Result.forkEffectScoped.InputContext<R, NoInfer<P>>>,
+    options?: useOnChangeResult.Options<A, E, P>,
+) {
+    const [result, setResult] = React.useState(() => Result.initial() as Result.Result<A, E, P>)
+
+    yield* useOnMount(() => Result.forkEffectScoped(f(), options).pipe(
+        Effect.andThen(Stream.fromQueue),
+        Stream.unwrap,
+        Stream.changesWith(options?.equivalence ?? Equivalence.strict()),
+        Stream.runForEach(result => Effect.sync(() => setResult(result))),
+    ))
+
+    return result
+})
+
+export namespace useOnChangeResult {
+    export interface Options<A, E, P>
+    extends useOnMountResult.Options<A, E, P>, useReactEffect.Options {}
+}
+
 export const useOnChangeResult: {
     <A, E, R, P = never>(
         f: () => Effect.Effect<A, E, Result.forkEffectScoped.InputContext<R, NoInfer<P>>>,