From f1d0771356e4345c0dd4113b2f80a32d1e837b46 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Julien=20Valverd=C3=A9?= <julien.valverde@mailo.com>
Date: Tue, 24 Mar 2026 11:51:38 +0100
Subject: [PATCH] Fix

---
 packages/effect-fc/src/Lens.test.ts | 20 ++++++++++----------
 packages/effect-fc/src/Lens.ts      | 18 +++++++++---------
 2 files changed, 19 insertions(+), 19 deletions(-)

diff --git a/packages/effect-fc/src/Lens.test.ts b/packages/effect-fc/src/Lens.test.ts
index 5ca7147..208d74a 100644
--- a/packages/effect-fc/src/Lens.test.ts
+++ b/packages/effect-fc/src/Lens.test.ts
@@ -4,12 +4,12 @@ import * as Lens from "./Lens.js"
 
 
 describe("Lens", () => {
-    test("mapField focuses a nested property without touching other fields", async () => {
+    test("focusField focuses a nested property without touching other fields", async () => {
         const [initialCount, updatedState] = await Effect.runPromise(
             Effect.flatMap(
                 SubscriptionRef.make({ count: 1, label: "original" }),
                 parent => {
-                    const countLens = Lens.mapField(Lens.fromSubscriptionRef(parent), "count")
+                    const countLens = Lens.focusField(Lens.fromSubscriptionRef(parent), "count")
                     return Effect.flatMap(
                         Lens.get(countLens),
                         count => Effect.flatMap(
@@ -25,13 +25,13 @@ describe("Lens", () => {
         expect(updatedState).toEqual({ count: 6, label: "original" })
     })
 
-    test("mapMutableField preserves the root identity when mutating in place", async () => {
+    test("focusMutableField preserves the root identity when mutating in place", async () => {
         const original = { detail: "keep" }
         const updated = await Effect.runPromise(
             Effect.flatMap(
                 SubscriptionRef.make(original),
                 parent => {
-                    const detailLens = Lens.mapMutableField(Lens.fromSubscriptionRef(parent), "detail")
+                    const detailLens = Lens.focusMutableField(Lens.fromSubscriptionRef(parent), "detail")
                     return Effect.flatMap(
                         Lens.set(detailLens, "mutated"),
                         () => parent.get,
@@ -44,12 +44,12 @@ describe("Lens", () => {
         expect(updated.detail).toBe("mutated")
     })
 
-    test("mapArrayAt updates the selected index", async () => {
+    test("focusArrayAt updates the selected index", async () => {
         const updated = await Effect.runPromise(
             Effect.flatMap(
                 SubscriptionRef.make([10, 20, 30]),
                 parent => {
-                    const elementLens = Lens.mapArrayAt(Lens.fromSubscriptionRef(parent), 1)
+                    const elementLens = Lens.focusArrayAt(Lens.fromSubscriptionRef(parent), 1)
                     return Effect.flatMap(
                         Lens.update(elementLens, value => value + 5),
                         () => parent.get,
@@ -61,13 +61,13 @@ describe("Lens", () => {
         expect(updated).toEqual([10, 25, 30])
     })
 
-    test("mapMutableArrayAt mutates the array reference in place", async () => {
+    test("focusMutableArrayAt mutates the array reference in place", async () => {
         const original = ["foo", "bar"]
         const updated = await Effect.runPromise(
             Effect.flatMap(
                 SubscriptionRef.make(original),
                 parent => {
-                    const elementLens = Lens.mapMutableArrayAt(Lens.fromSubscriptionRef(parent), 0)
+                    const elementLens = Lens.focusMutableArrayAt(Lens.fromSubscriptionRef(parent), 0)
                     return Effect.flatMap(
                         Lens.set(elementLens, "baz"),
                         () => parent.get,
@@ -80,12 +80,12 @@ describe("Lens", () => {
         expect(updated).toEqual(["baz", "bar"])
     })
 
-    test("mapChunkAt replaces the focused chunk element", async () => {
+    test("focusChunkAt replaces the focused chunk element", async () => {
         const updated = await Effect.runPromise(
             Effect.flatMap(
                 SubscriptionRef.make(Chunk.make(1, 2, 3) as Chunk.Chunk<number>),
                 parent => {
-                    const elementLens = Lens.mapChunkAt(Lens.fromSubscriptionRef(parent), 2)
+                    const elementLens = Lens.focusChunkAt(Lens.fromSubscriptionRef(parent), 2)
                     return Effect.flatMap(
                         Lens.set(elementLens, 99),
                         () => parent.get,
diff --git a/packages/effect-fc/src/Lens.ts b/packages/effect-fc/src/Lens.ts
index 3c8e23f..1b2f19a 100644
--- a/packages/effect-fc/src/Lens.ts
+++ b/packages/effect-fc/src/Lens.ts
@@ -157,7 +157,7 @@ export const mapStream: {
 }))
 
 
-export const mapField: {
+export const focusField: {
     <A extends object, K extends keyof A, ER, EW, RR, RW>(
         self: Lens<A, ER, EW, RR, RW>,
         key: K,
@@ -174,7 +174,7 @@ export const mapField: {
     (a, b) => Object.setPrototypeOf({ ...a, [key]: b }, Object.getPrototypeOf(a)),
 ))
 
-export declare namespace mapMutableField {
+export declare namespace focusMutableField {
     export type WritableKeys<T> = {
         [K in keyof T]-?: IfEquals<
             { [P in K]: T[K] },
@@ -187,20 +187,20 @@ export declare namespace mapMutableField {
     type IfEquals<X, Y, A = X, B = never> = (<T>() => T extends X ? 1 : 2) extends (<T>() => T extends Y ? 1 : 2) ? A : B
 }
 
-export const mapMutableField: {
-    <A extends object, K extends mapMutableField.WritableKeys<A>, ER, EW, RR, RW>(
+export const focusMutableField: {
+    <A extends object, K extends focusMutableField.WritableKeys<A>, ER, EW, RR, RW>(
         self: Lens<A, ER, EW, RR, RW>,
         key: K,
     ): Lens<A[K], ER, EW, RR, RW>
-    <A extends object, K extends mapMutableField.WritableKeys<A>, ER, EW, RR, RW>(
+    <A extends object, K extends focusMutableField.WritableKeys<A>, ER, EW, RR, RW>(
         key: K,
     ): (self: Lens<A, ER, EW, RR, RW>) => Lens<A[K], ER, EW, RR, RW>
-} = Function.dual(2, <A extends object, K extends mapMutableField.WritableKeys<A>, ER, EW, RR, RW>(
+} = Function.dual(2, <A extends object, K extends focusMutableField.WritableKeys<A>, ER, EW, RR, RW>(
     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 }))
 
-export const mapArrayAt: {
+export const focusArrayAt: {
     <A extends readonly any[], ER, EW, RR, RW>(
         self: Lens<A, ER, EW, RR, RW>,
         index: number,
@@ -217,7 +217,7 @@ export const mapArrayAt: {
     (a, b) => Array.replaceOption(a, index, b) as any,
 ))
 
-export const mapMutableArrayAt: {
+export const focusMutableArrayAt: {
     <A, ER, EW, RR, RW>(
         self: Lens<A[], ER, EW, RR, RW>,
         index: number,
@@ -237,7 +237,7 @@ export const mapMutableArrayAt: {
     ),
 ))
 
-export const mapChunkAt: {
+export const focusChunkAt: {
     <A, ER, EW, RR, RW>(
         self: Lens<Chunk.Chunk<A>, ER, EW, RR, RW>,
         index: number,