chore(msw): upgrade MSW to v3 while keeping v2 support

apps/content/docs/integrations/msw.mdx

@@ -15,6 +15,10 @@ This guide assumes you are already familiar with [MSW](https://mswjs.io/). If yo
 npm install @orpc/experimental-msw@beta
 ```
 
+:::info
+Both MSW v2 and v3 are supported.
+:::
+
 ## Setup
 
 Create MSW utils from a [router contract](/docs/contract/router) or an implemented [router](/docs/router) (convert [lazy routers](/docs/router#lazy-router) with [`unlazyRouter`](/docs/contract/router#router-to-contract) first). The `handler` option creates the fetch handler that serves each mock. Configure it like your production handler, so serialization, validation, and error envelopes behave exactly like your real server.
@@ -91,7 +95,7 @@ export const Loading: Story = {
 
 ## Passthrough
 
-The `.passthrough` method creates an MSW request handler that performs matching requests against the real server as-is, useful to exempt specific procedures from mocking, for example while [onUnhandledRequest](https://mswjs.io/docs/api/setup-server/listen#onunhandledrequest) treats everything else as an error:
+The `.passthrough` method creates an MSW request handler that performs matching requests against the real server as-is, useful to exempt specific procedures from mocking, for example while [onUnhandledFrame](https://mswjs.io/docs/api/setup-server/listen) (`onUnhandledRequest` in MSW v2) treats everything else as an error:
 
 ```ts
 const handlers = [

packages/msw/package.json

@@ -52,7 +52,8 @@
   },
   "devDependencies": {
     "@orpc/openapi": "workspace:*",
-    "msw": "^2.15.0",
+    "msw": "^3.0.2",
+    "msw-v2": "npm:msw@^2.15.0",
     "zod": "^4.6.5"
   }
 }

packages/msw/src/http-procedure-utils.openapi.test.ts

@@ -31,7 +31,7 @@ const contract = {
 
 const server = setupServer()
 
-beforeAll(() => server.listen({ onUnhandledRequest: 'error' }))
+beforeAll(() => server.listen({ onUnhandledFrame: 'error' }))
 afterEach(() => server.resetHandlers())
 afterAll(() => server.close())
 

packages/msw/src/http-procedure-utils.test.ts

@@ -29,7 +29,7 @@ const contract = {
 
 const server = setupServer()
 
-beforeAll(() => server.listen({ onUnhandledRequest: 'error' }))
+beforeAll(() => server.listen({ onUnhandledFrame: 'error' }))
 afterEach(() => server.resetHandlers())
 afterAll(() => server.close())
 

packages/msw/src/http-router-utils.test.ts

@@ -43,7 +43,7 @@ describe('with an implemented router', () => {
 
   const server = setupServer()
 
-  beforeAll(() => server.listen({ onUnhandledRequest: 'error' }))
+  beforeAll(() => server.listen({ onUnhandledFrame: 'error' }))
   afterEach(() => server.resetHandlers())
   afterAll(() => server.close())
 

vitest.config.ts

@@ -33,7 +33,29 @@ export default defineConfig(({ mode }) => ({
           globals: true,
           setupFiles: ['./vitest.javascript.ts'],
           include: ['**/*.test.ts'],
-          exclude: [...defaultExclude, '**/.claude/**', './packages/bun/**', './packages/cloudflare/**'],
+          exclude: [
+            ...defaultExclude,
+            '**/.claude/**',
+            './packages/bun/**',
+            './packages/cloudflare/**',
+            // MSW v3 requires Node.js 22+, older versions only run the MSW v2 project below
+            ...(Number.parseInt(process.versions.node) < 22 ? ['./packages/msw/**'] : []),
+          ],
+          benchmark: {
+            exclude: ['**/**'],
+          },
+        },
+      },
+      {
+        // also test @orpc/experimental-msw against MSW v2
+        resolve: {
+          alias: { msw: 'msw-v2' },
+        },
+        test: {
+          name: 'msw-v2',
+          globals: true,
+          setupFiles: ['./vitest.javascript.ts'],
+          include: ['./packages/msw/**/*.test.ts'],
           benchmark: {
             exclude: ['**/**'],
           },