Add support for Nuxt 4

[marcospassos]

Summary

Installing @croct/plug-nuxt in a Nuxt 4 app fails with ERESOLVE, since the peer range is still nuxt@^3.0.0. This widens the range, fixes the Nuxt 4 regressions that widening exposed, and moves the test toolchain to Nuxt 4 while keeping Nuxt 3 covered in CI.

Changes

Support

• peerDependencies.nuxt: ^3.0.0 → ^3.0.0 || ^4.0.0
• dependencies["@nuxt/kit"]: ^3.17.5 → ^3.17.5 || ^4.0.0. Left at ^3, npm nests a second kit under the module; widened, it dedupes to the host's copy.

Nuxt 4 fix

Nuxt 4 changed the default of useAsyncData's data and error from null to undefined. Personalization checked error.value !== null before anything else, so every successful render took the error branch and threw a 500 (Cannot read properties of undefined (reading 'message')). Slot had the same check but escaped because it tests data first. Both now treat undefined as no error.

Tests

• @nuxt/test-utils 3 → 4 and vitest 3 → 4; the nuxt dev dependency moves to ^4.5.2. With test-utils 3, the nuxt vitest environment fails to boot under Nuxt 4.
• Four test files read the runtime config in the describe body. Nuxt 4 has no app instance while the module evaluates, so they now do it in beforeAll.
• The e2e job runs as a matrix over Nuxt 3 and 4. The lockfile pins Nuxt 4, and the Nuxt 3 leg downgrades nuxt and @nuxt/kit together; downgrading only nuxt leaves kit 4 hoisted, so the module would run kit 4 against a Nuxt 3 app.
• Added a waitForHydration() e2e helper. Clicking a NuxtLink before hydration performs a full document navigation, so the client-navigation specs were asserting the server-rendered context instead. Nuxt 4 dev hydrates slowly enough to expose this; identity.spec.ts had the same race and was passing for the wrong reason.

Tooling

• @nuxt/module-builder 0.8 → 1.0. v1 drops the Nuxt-3-only kit peer. It emits the module entry declarations as .d.mts, so exports["."].types and types point there now. The runtime declarations are still .d.ts, so ./types and ./csr are unchanged.
• prepare is no longer published. npm runs it for git and tarball installs, where e2e/app doesn't exist. tsc needs the generated #imports types, so validate now runs nuxi prepare e2e/app itself, and dev:prepare stays for editor support.
• Lint was failing on master. @croct/eslint-plugin sets no import resolver, so import-x falls back to the legacy node one, which isn't installed. Its last fallback resolves <package>/node as a path, and once no-cycle walked into node_modules, it loaded lightningcss/node (native bindings) as the resolver and crashed the run. An explicit eslint-import-resolver-typescript resolver fixes it, and also resolves #app and #imports through the tsconfig paths.

Verification

	Nuxt 4 (lockfile)	Nuxt 3 (matrix leg)
lint	pass	—
validate	pass	—
unit (115)	pass	—
build	pass	pass
e2e (69)	pass	pass
prerender e2e (3)	pass	pass

Both Nuxt 4 e2e failures were reproduced first, and both specs were confirmed to pass on Nuxt 3, so neither was a flake.

Type resolution after the .d.mts move was checked against the packed tarball in a scratch consumer: imports of @croct/plug-nuxt, /types and /csr typecheck under both moduleResolution: bundler and nodenext. A negative control ({appId: 42}) fails as expected, so the types are really loaded rather than falling back to any.

End to end, the packed tarball installs into a Nuxt 4.5.2 app without overrides or ERESOLVE, with a single @nuxt/kit, and the app builds with both /api/_croct/* handlers registered.

Notes

• Unit tests run on Nuxt 4 only; test-utils 4 doesn't support Nuxt 3. Nuxt 3 keeps full e2e coverage.
• nuxt@4.5.2 requires Node ^22.19.0 || ^24.11.0. On older Node, ^4.0.0 silently resolves to 4.4.5, whose exact kit pin nests a second @nuxt/schema and breaks tsc. That's why the dev dependency is pinned to ^4.5.2. CI's Node 22 is unaffected.
• import-x/no-cycle runs now, but it doesn't report a planted two-file cycle, even with maxDepth raised. That's a limitation of the import-x build bundled into @croct/eslint-plugin, not something this PR can fix.

[pkg-pr-new]

Open in StackBlitz

npm i https://pkg.pr.new/@croct/plug-nuxt@13

commit: 3b96eb2