From 1e068af09c5d4c41d3387185148b0c63d7b42a43 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Julien=20Valverd=C3=A9?= <julien.valverde@mailo.com>
Date: Mon, 30 Mar 2026 13:27:54 +0200
Subject: [PATCH 1/3] Add Subscribable utils

---
 packages/effect-lens/src/Subscribable.ts | 37 +++++++++++++++++++++++-
 1 file changed, 36 insertions(+), 1 deletion(-)

diff --git a/packages/effect-lens/src/Subscribable.ts b/packages/effect-lens/src/Subscribable.ts
index c88a108..10cf991 100644
--- a/packages/effect-lens/src/Subscribable.ts
+++ b/packages/effect-lens/src/Subscribable.ts
@@ -1,9 +1,44 @@
-import { Array, Chunk, Function, Subscribable } from "effect"
+import { Array, Chunk, Effect, Function, Option, Subscribable } from "effect"
 import type { NoSuchElementException } from "effect/Cause"
 
 
 export * from "effect/Subscribable"
 
+/**
+ * Maps over an `Option` value in the `Subscribable`.
+ */
+export const mapOption: {
+    <A, B, E, R>(
+        self: Subscribable.Subscribable<Option.Option<A>, E, R>,
+        f: (a: A) => B,
+    ): Subscribable.Subscribable<Option.Option<B>, E, R>
+    <A, B>(
+        f: (a: A) => B,
+    ): <E, R>(self: Subscribable.Subscribable<Option.Option<A>, E, R>) => Subscribable.Subscribable<Option.Option<B>, E, R>
+} = Function.dual(2, <A, B, E, R>(
+    self: Subscribable.Subscribable<Option.Option<A>, E, R>,
+    f: (a: A) => B,
+): Subscribable.Subscribable<Option.Option<B>, E, R> => Subscribable.map(self, Option.map(f)))
+
+/**
+ * Maps over an `Option` value in the `Subscribable` with an Effect.
+ */
+export const mapOptionEffect: {
+    <A, B, E, E2, R>(
+        self: Subscribable.Subscribable<Option.Option<A>, E, R>,
+        f: (a: A) => Effect.Effect<B, E2, R>,
+    ): Subscribable.Subscribable<Option.Option<B>, E | E2, R>
+    <A, B, E2>(
+        f: (a: A) => Effect.Effect<B, E2>,
+    ): <E, R>(self: Subscribable.Subscribable<Option.Option<A>, E, R>) => Subscribable.Subscribable<Option.Option<B>, E | E2, R>
+} = Function.dual(2, <A, B, E, E2, R>(
+    self: Subscribable.Subscribable<Option.Option<A>, E, R>,
+    f: (a: A) => Effect.Effect<B, E2, R>,
+): Subscribable.Subscribable<Option.Option<B>, E | E2, R> => Subscribable.mapEffect(self, Option.match({
+    onSome: a => Effect.map(f(a), Option.some),
+    onNone: () => Effect.succeed(Option.none()),
+})))
+
 /**
  * Narrows the focus to a field of an object.
  */
-- 
2.49.1


From 41e8685f3687c229abc51085b4a941118ef624bc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Julien=20Valverd=C3=A9?= <julien.valverde@mailo.com>
Date: Mon, 30 Mar 2026 14:11:01 +0200
Subject: [PATCH 2/3] Fix

---
 packages/effect-lens/src/Lens.ts | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/packages/effect-lens/src/Lens.ts b/packages/effect-lens/src/Lens.ts
index f265eee..bdb5ffe 100644
--- a/packages/effect-lens/src/Lens.ts
+++ b/packages/effect-lens/src/Lens.ts
@@ -274,14 +274,14 @@ export const mapStream: {
  * Narrows the focus to a field of an object. Replaces the object in an immutable fashion when written to.
  */
 export const focusObjectField: {
-    <A extends object, K extends keyof A, ER, EW, RR, RW>(
+    <A extends object, ER, EW, RR, RW, K extends keyof A>(
         self: Lens<A, ER, EW, RR, RW>,
         key: K,
     ): Lens<A[K], ER, EW, RR, RW>
-    <A extends object, K extends keyof A, ER, EW, RR, RW>(
+    <A extends object, ER, EW, RR, RW, K extends keyof A>(
         key: K,
     ): (self: Lens<A, ER, EW, RR, RW>) => Lens<A[K], ER, EW, RR, RW>
-} = Function.dual(2, <A extends object, K extends keyof A, ER, EW, RR, RW>(
+} = Function.dual(2, <A extends object, ER, EW, RR, RW, K extends keyof A>(
     self: Lens<A, ER, EW, RR, RW>,
     key: K,
 ): Lens<A[K], ER, EW, RR, RW> => map(
@@ -307,14 +307,14 @@ export declare namespace focusObjectMutableField {
  * Narrows the focus to a mutable field of an object. Mutates the object in place when written to.
  */
 export const focusObjectMutableField: {
-    <A extends object, K extends focusObjectMutableField.WritableKeys<A>, ER, EW, RR, RW>(
+    <A extends object, ER, EW, RR, RW, K extends focusObjectMutableField.WritableKeys<A>>(
         self: Lens<A, ER, EW, RR, RW>,
         key: K,
     ): Lens<A[K], ER, EW, RR, RW>
-    <A extends object, K extends focusObjectMutableField.WritableKeys<A>, ER, EW, RR, RW>(
+    <A extends object, ER, EW, RR, RW, K extends focusObjectMutableField.WritableKeys<A>>(
         key: K,
     ): (self: Lens<A, ER, EW, RR, RW>) => Lens<A[K], ER, EW, RR, RW>
-} = Function.dual(2, <A extends object, K extends focusObjectMutableField.WritableKeys<A>, ER, EW, RR, RW>(
+} = Function.dual(2, <A extends object, ER, EW, RR, RW, K extends focusObjectMutableField.WritableKeys<A>>(
     self: Lens<A, ER, EW, RR, RW>,
     key: K,
 ): Lens<A[K], ER, EW, RR, RW> => map(self, a => a[key], (a, b) => { a[key] = b; return a }))
@@ -366,14 +366,14 @@ export const focusMutableArrayAt: {
  * Narrows the focus to an indexed element of a readonly tuple. Replaces the tuple in an immutable fashion when written to.
  */
 export const focusTupleAt: {
-    <T extends readonly [any, ...any[]], I extends number, ER, EW, RR, RW>(
+    <T extends readonly [any, ...any[]], ER, EW, RR, RW, I extends number>(
         self: Lens<T, ER, EW, RR, RW>,
         index: I,
     ): Lens<T[I], ER, EW, RR, RW>
-    <T extends readonly [any, ...any[]], I extends number, ER, EW, RR, RW>(
+    <T extends readonly [any, ...any[]], ER, EW, RR, RW, I extends number>(
         index: I
     ): (self: Lens<T, ER, EW, RR, RW>) => Lens<T[I], ER, EW, RR, RW>
-} = Function.dual(2, <T extends readonly [any, ...any[]], I extends number, ER, EW, RR, RW>(
+} = Function.dual(2, <T extends readonly [any, ...any[]], ER, EW, RR, RW, I extends number>(
     self: Lens<T, ER, EW, RR, RW>,
     index: I,
 ): Lens<T[I], ER, EW, RR, RW> => map(
@@ -386,14 +386,14 @@ export const focusTupleAt: {
  * Narrows the focus to an indexed element of a mutable tuple. Mutates the tuple in place when written to.
  */
 export const focusMutableTupleAt: {
-    <T extends [any, ...any[]], I extends number, ER, EW, RR, RW>(
+    <T extends [any, ...any[]], ER, EW, RR, RW, I extends number>(
         self: Lens<T, ER, EW, RR, RW>,
         index: I,
     ): Lens<T[I], ER, EW, RR, RW>
-    <T extends [any, ...any[]], I extends number, ER, EW, RR, RW>(
+    <T extends [any, ...any[]], ER, EW, RR, RW, I extends number>(
         index: I
     ): (self: Lens<T, ER, EW, RR, RW>) => Lens<T[I], ER, EW, RR, RW>
-} = Function.dual(2, <T extends [any, ...any[]], I extends number, ER, EW, RR, RW>(
+} = Function.dual(2, <T extends [any, ...any[]], ER, EW, RR, RW, I extends number>(
     self: Lens<T, ER, EW, RR, RW>,
     index: I,
 ): Lens<T[I], ER, EW, RR, RW> => map(
-- 
2.49.1


From eb270acce407fdcdd0e3e495e1cf589d538b4cf6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Julien=20Valverd=C3=A9?= <julien.valverde@mailo.com>
Date: Mon, 30 Mar 2026 14:11:29 +0200
Subject: [PATCH 3/3] Bump version

---
 packages/effect-lens/package.json | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/effect-lens/package.json b/packages/effect-lens/package.json
index f5b0f5f..5e3a238 100644
--- a/packages/effect-lens/package.json
+++ b/packages/effect-lens/package.json
@@ -1,7 +1,7 @@
 {
   "name": "effect-lens",
   "description": "An effectful Lens type to easily manage nested state",
-  "version": "0.1.3",
+  "version": "0.1.4",
   "type": "module",
   "files": [
     "./README.md",
-- 
2.49.1