From 88a4b9286d1eb9c9a55e1cbdec87fb72463b9e60 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Julien=20Valverd=C3=A9?= <julien.valverde@mailo.com>
Date: Fri, 22 May 2026 01:23:33 +0200
Subject: [PATCH] Refactor

---
 packages/effect-lens/src/Lens.ts | 22 +++++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/packages/effect-lens/src/Lens.ts b/packages/effect-lens/src/Lens.ts
index e9bf203..82eabc0 100644
--- a/packages/effect-lens/src/Lens.ts
+++ b/packages/effect-lens/src/Lens.ts
@@ -34,6 +34,7 @@ export type LensStepTypeId = typeof LensTypeId
 export interface LensStep<in out A, in out B, in out ER = never, in out EW = never, in out RR = never, in out RW = never> {
     readonly [LensStepTypeId]: LensStepTypeId
     readonly transform: (parent: B) => Effect.Effect<A, ER, RR>
+    readonly transformStream: (parent: B) => Stream.Stream<A, ER, RR>
     readonly update: (next: A, parent: B) => Effect.Effect<B, EW, RW>
 }
 
@@ -52,18 +53,29 @@ export const isLensStep = (u: unknown): u is LensStep<unknown, unknown, unknown,
 export const LensImplTypeId: unique symbol = Symbol.for("@effect-fc/Lens/LensImpl")
 export type LensImplTypeId = typeof LensImplTypeId
 
-export abstract class LensImpl<in out A, in out ER = never, in out EW = never, in out RR = never, in out RW = never>
+export abstract class LensImpl<
+    in out A,
+    in out B,
+    in out ER = never,
+    in out EW = never,
+    in out RR = never,
+    in out RW = never,
+    in out SourceER = never,
+    in out SourceEW = never,
+    in out SourceRR = never,
+    in out SourceRW = never,
+>
 extends Pipeable.Class() implements Lens<A, ER, EW, RR, RW> {
     readonly [Readable.TypeId]: Readable.TypeId = Readable.TypeId
     readonly [Subscribable.TypeId]: Subscribable.TypeId = Subscribable.TypeId
     readonly [LensTypeId]: LensTypeId = LensTypeId
     readonly [LensImplTypeId]: LensImplTypeId = LensImplTypeId
 
-    readonly steps: readonly LensStep<A, ER, EW, RR, RW>[] = []
+    readonly steps: readonly LensStep<B, SER, SEW, SRR, SRW>[] = []
 
-    abstract readonly sourceGet: Effect.Effect<A, ER, RR>
-    abstract readonly sourceChanges: Stream.Stream<A, ER, RR>
-    abstract readonly sourceCommit: (a: A) => Effect.Effect<void, EW, RW>
+    abstract readonly sourceGet: Effect.Effect<B, SourceER, SourceRR>
+    abstract readonly sourceChanges: Stream.Stream<B, SourceER, SourceRR>
+    abstract readonly sourceCommit: (b: B) => Effect.Effect<void, SourceEW, SourceRW>
     abstract readonly withLock: <A1, E1, R1>(self: Effect.Effect<A1, E1, R1>) => Effect.Effect<A1, EW | E1, RW | R1>
 
     get get(): Effect.Effect<A, ER, RR> {