chore(deps): upgrade immer 9 → 11 (#1035)

* chore(deps): upgrade immer 9 → 11

- Bump immer from ^9.0.21 to ^11.1.4
- Drop useProxies option in src/lib.js — immer v10 dropped ES5 mode and
  Proxy is now the only supported backend
- Remove easy-peasy/proxy-polyfill subpath export — enableES5() no longer
  exists in immer
- Document the subpath removal as a v7 breaking change in the upgrade guide
- Keep easy-peasy/map-set-support — enableMapSet() is still opt-in in v11

Closes #1034

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* docs(v7): rewrite browser-support page for immer v11

The proxy-polyfill subpath documented here was removed in #1035 — immer v10
dropped ES5 mode entirely, so the IE11 / non-Proxy environment workflow
described on this page no longer applies.

- Drop the "Polyfilling Proxy" and "Create React App IE11 Support" sections.
- Reframe the page around React 19's supported runtimes (all ship native
  Proxy).
- Keep the "Why Immer?" overview and the Map/Set support section.
- Add a v6 → v7 migration callout pointing at the upgrade guide for
  consumers who imported the removed subpath.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: ctrlplusb

package.json

@@ -19,16 +19,13 @@
       "import": "./dist/server.js",
       "require": "./dist/server.cjs.js"
     },
-    "./map-set-support": "./map-set-support.js",
-    "./proxy-polyfill": "./proxy-polyfill.js"
+    "./map-set-support": "./map-set-support.js"
   },
   "files": [
     "dist",
     "src",
     "index.d.ts",
     "server.d.ts",
-    "proxy-polyfill.js",
-    "proxy-polyfill.d.ts",
     "map-set-support.js",
     "map-set-support.d.ts"
   ],
@@ -100,7 +97,7 @@
   },
   "dependencies": {
     "fast-deep-equal": "^3.1.3",
-    "immer": "^9.0.21",
+    "immer": "^11.1.4",
     "redux": "^5.0.1",
     "redux-thunk": "^3.1.0",
     "ts-toolbelt": "^9.6.0"

proxy-polyfill.d.ts

@@ -96,13 +96,6 @@ export function createSimpleProduce(disableImmer = false) {
     }
     if (!easyPeasyImmer) {
       easyPeasyImmer = new Immer({
-        // We need to ensure that we disable proxies if they aren't available
-        // on the environment. Users need to ensure that they use the enableES5
-        // feature of immer.
-        useProxies:
-          typeof Proxy !== 'undefined' &&
-          typeof Proxy.revocable !== 'undefined' &&
-          typeof Reflect !== 'undefined',
         // Autofreezing breaks easy-peasy, we need a mixed version of immutability
         // and mutability in order to apply updates to our computed properties
         autoFreeze: false,

proxy-polyfill.js

@@ -1,27 +1,17 @@
 # Browsers & React Native
 
-Easy Peasy produces multiple bundle types - support for browsers, Common JS, and
-ESM.
-
-However, due to our internal usage of [Immer](https://github.com/immerjs/immer)
-your code may break on some older browsers (e.g. IE 11) or some older React
-Native environments.
-
-Specifically it will break on [environments](https://caniuse.com/?search=proxy)
-that don't support
-[proxies](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy).
-
-We provide a solution to this, however, before we present the solution we would
-like to describe our motivation for implementing Immer.
+Easy Peasy ships ESM and CommonJS bundles. The library targets the same
+environments that React 19 supports — modern evergreen browsers and current
+React Native runtimes.
 
 - [Why Immer?](#why-immer)
-- [Polyfilling Proxy](#polyfilling-proxy)
-  - [Create React App IE11 Support Example](#create-react-app-ie11-support-example)
+- [Proxy is required](#proxy-is-required)
 - [Supporting Map or Set within your state](#supporting-map-or-set-within-your-state)
 
 ## Why Immer?
 
-Immer powers our mutation based API that is supported within actions.
+Easy Peasy uses [Immer](https://github.com/immerjs/immer) to power the
+mutation-based API supported within actions:
 
 ```javascript
 addTodo: action((state, payload) => {
@@ -31,12 +21,10 @@ addTodo: action((state, payload) => {
 });
 ```
 
-[Immer](https://github.com/immerjs/immer) converts these mutation operations
-into immutable updates against the store.
-
-This allows for a much improved developer experience as having to manage
-immutable update operations yourself can become quite complex. For example here
-is the same action above written to ensure immutability is met manually.
+Immer converts these mutation operations into immutable updates against the
+store. This is a much improved developer experience over managing immutable
+updates yourself, particularly for deeply nested state. The same action
+without Immer would look like:
 
 ```javascript
 addTodo: action((state, payload) => {
@@ -47,55 +35,29 @@ addTodo: action((state, payload) => {
 });
 ```
 
-That's just a simple example. More complex/nested updates can get very tricky to
-manage.
-
-## Polyfilling Proxy
-
-If you are getting errors on your console - typically error code 19 or 20 from
-the Immer package then your execution environment likely does not support
-[proxies](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy).
-
-To patch/polyfill your environment you need to include the following import.
-
-```javascript
-import 'easy-peasy/proxy-polyfill';
-```
-
-This should typically be done as early as possible within the entry file of your
-application.
-
-### Create React App IE11 Support Example
+## Proxy is required
 
-Create React App users will likely need to include a configuration like so,
-which includes full IE11 support;
+Immer relies on the
+[`Proxy`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Proxy)
+global. Every browser in React 19's
+[supported list](https://react.dev/reference/react/version-history) ships
+native `Proxy`, as do all current React Native runtimes (Hermes, JSC), so no
+polyfill is required.
 
-```javascript
-import 'react-app-polyfill/ie11';
-import 'react-app-polyfill/stable';
-import 'easy-peasy/proxy-polyfill';
-```
-
-Also, don't forget to update your browserslist within your `package.json`.
-
-```diff
-   "browserslist": [
-+    "ie 11",
-     ">0.2%",
-     "not dead",
-     "not ie <= 10",
-     "not op_mini all"
-   ]
-```
+> **Migrating from v6?** Easy Peasy v6 shipped an `easy-peasy/proxy-polyfill`
+> subpath that opted Immer into an ES5 fallback for environments without
+> native `Proxy` (notably IE11). v7 upgrades to Immer v11, which removed ES5
+> mode entirely, so the subpath has been deleted. Remove any
+> `import 'easy-peasy/proxy-polyfill';` lines — see the
+> [v6 → v7 upgrade guide](/docs/upgrading-from-v6/#easy-peasyproxy-polyfill-subpath-removed)
+> for details.
 
 ## Supporting Map or Set within your state
 
-In order to utilize `Map` or `Set` within your state you need to include the
-following import.
+To use `Map` or `Set` within your state you need to opt into Immer's
+[Map/Set support](https://immerjs.github.io/immer/map-set/) by importing the
+following module as early as possible in your application's entry file:
 
 ```javascript
 import 'easy-peasy/map-set-support';
 ```
-
-Similarly to the Proxy polyfill you will need to do this as early as possible
-within your application entry file.

src/lib.js

@@ -12,6 +12,7 @@ This guide walks you through the breaking changes and the new APIs.
 - [Breaking changes](#breaking-changes)
   - [React 19 is required](#react-19-is-required)
   - [`useStoreRehydrated` now suspends](#usestorerehydrated-now-suspends)
+  - [`easy-peasy/proxy-polyfill` subpath removed](#easy-peasyproxy-polyfill-subpath-removed)
 - [New APIs](#new-apis)
   - [`useStoreTransition`](#usestoretransition)
   - [`useStoreDeferredState`](#usestoredeferredstate)
@@ -113,6 +114,25 @@ If you previously wrote a wrapper component:
 > React deliver the rehydrated tree in a single render once the data is ready,
 > with no flash of default state.
 
+### `easy-peasy/proxy-polyfill` subpath removed
+
+v6 shipped an `easy-peasy/proxy-polyfill` subpath which called immer's
+`enableES5()` helper to support environments without native `Proxy` (notably
+IE11). Easy Peasy v7 upgrades to immer v11, which dropped ES5 mode entirely —
+`Proxy` is now the only supported backend.
+
+If you imported the subpath:
+
+```diff
+- import 'easy-peasy/proxy-polyfill';
+```
+
+…remove the import. Every browser supported by React 19 has native `Proxy`, so
+no replacement is needed.
+
+The `easy-peasy/map-set-support` subpath (which calls `enableMapSet()`) is
+unchanged — Map/Set draft support is still opt-in in immer v11.
+
 ## New APIs
 
 ### `useStoreTransition`

website/docs/docs/introduction/browser-support.md

@@ -2641,10 +2641,10 @@ ignore@^5.2.0:
   resolved "https://registry.yarnpkg.com/ignore/-/ignore-5.3.2.tgz#3cd40e729f3643fd87cb04e50bf0eb722bc596f5"
   integrity sha512-hsBTNUqQTDwkWtcdYI2i06Y/nUBEsNEDJKjWdigLvegy8kDuJAS8uRlpkkcQpyEXL0Z/pjDy5HBmMjRCJ2gq+g==
 
-immer@^9.0.21:
-  version "9.0.21"
-  resolved "https://registry.yarnpkg.com/immer/-/immer-9.0.21.tgz#1e025ea31a40f24fb064f1fef23e931496330176"
-  integrity sha512-bc4NBHqOqSfRW7POMkHd51LvClaeMXpm8dx0e8oE2GORbq5aRK7Bxl4FyzVLdGtLmvLKL7BTDBG5ACQm4HWjTA==
+immer@^11.1.4:
+  version "11.1.4"
+  resolved "https://registry.yarnpkg.com/immer/-/immer-11.1.4.tgz#37aee86890b134a8f1a2fadd44361fb86c6ae67e"
+  integrity sha512-XREFCPo6ksxVzP4E0ekD5aMdf8WMwmdNaz6vuvxgI40UaEiu6q3p8X52aU6GdyvLY3XXX/8R7JOTXStz/nBbRw==
 
 import-fresh@^3.2.1:
   version "3.3.1"