From 677becc9079da49021c0de72eb873a7191815209 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mateusz=20Burzy=C5=84ski?= <mateuszburzynski@gmail.com>
Date: Sat, 9 Mar 2024 12:00:28 +0100
Subject: [PATCH] Limit the change to `applyPatches`

---
 __tests__/produce.ts        | 17 ++++++++++++++++-
 src/core/immerClass.ts      | 16 ++++++----------
 src/types/types-external.ts |  7 ++-----
 3 files changed, 24 insertions(+), 16 deletions(-)

diff --git a/__tests__/produce.ts b/__tests__/produce.ts
index 22f0a318..f9093688 100644
--- a/__tests__/produce.ts
+++ b/__tests__/produce.ts
@@ -8,7 +8,8 @@ import {
 	Immutable,
 	Immer,
 	enableMapSet,
-	enablePatches
+	enablePatches,
+	produceWithPatches
 } from "../src/immer"
 
 enableMapSet()
@@ -162,6 +163,20 @@ it("can apply patches", () => {
 	expect(applyPatches({}, patches)).toEqual({x: 4})
 })
 
+it("can apply readonly patches", () => {
+	const [, patches]: readonly [
+		{
+			x: number
+		},
+		readonly Patch[],
+		readonly Patch[]
+	] = produceWithPatches({x: 3}, d => {
+		d.x++
+	})
+
+	expect(applyPatches({}, patches)).toEqual({x: 4})
+})
+
 describe("curried producer", () => {
 	it("supports rest parameters", () => {
 		type State = {readonly a: 1}
diff --git a/src/core/immerClass.ts b/src/core/immerClass.ts
index ed04e9f2..b7ac51b3 100644
--- a/src/core/immerClass.ts
+++ b/src/core/immerClass.ts
@@ -120,15 +120,11 @@ export class Immer implements ProducersFns {
 				this.produceWithPatches(state, (draft: any) => base(draft, ...args))
 		}
 
-		let patches: readonly Patch[], inversePatches: readonly Patch[]
-		const result = this.produce(
-			base,
-			recipe,
-			(p: readonly Patch[], ip: readonly Patch[]) => {
-				patches = p
-				inversePatches = ip
-			}
-		)
+		let patches: Patch[], inversePatches: Patch[]
+		const result = this.produce(base, recipe, (p: Patch[], ip: Patch[]) => {
+			patches = p
+			inversePatches = ip
+		})
 		return [result, patches!, inversePatches!]
 	}
 
@@ -171,7 +167,7 @@ export class Immer implements ProducersFns {
 		this.useStrictShallowCopy_ = value
 	}
 
-	applyPatches<T extends Objectish>(base: T, patches: Patch[]): T {
+	applyPatches<T extends Objectish>(base: T, patches: readonly Patch[]): T {
 		// If a patch replaces the entire state, take that replacement as base
 		// before applying patches
 		let i: number
diff --git a/src/types/types-external.ts b/src/types/types-external.ts
index 717df9b4..8bb44aba 100644
--- a/src/types/types-external.ts
+++ b/src/types/types-external.ts
@@ -68,10 +68,7 @@ export interface Patch {
 	value?: any
 }
 
-export type PatchListener = (
-	patches: readonly Patch[],
-	inversePatches: readonly Patch[]
-) => void
+export type PatchListener = (patches: Patch[], inversePatches: Patch[]) => void
 
 /** Converts `nothing` into `undefined` */
 type FromNothing<T> = T extends typeof NOTHING ? undefined : T
@@ -84,7 +81,7 @@ export type Produced<Base, Return> = Return extends void
 /**
  * Utility types
  */
-type PatchesTuple<T> = readonly [T, readonly Patch[], readonly Patch[]]
+type PatchesTuple<T> = readonly [T, Patch[], Patch[]]
 
 type ValidRecipeReturnType<State> =
 	| State