Applies the same interop as we did for `next/jest` in #36824
We could potentially apply the same for other submodules, or do it on
the basis of someone hitting the issue.
Fixes#43206
## Bug
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Errors have a helpful link attached, see `contributing.md`
## Feature
- [ ] Implements an existing feature request or RFC. Make sure the
feature request has been accepted for implementation before opening a
PR.
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Documentation added
- [ ] Telemetry added. In case of a feature if it's used or not.
- [ ] Errors have a helpful link attached, see `contributing.md`
## Documentation / Examples
- [ ] Make sure the linting passes by running `pnpm build && pnpm lint`
- [ ] The "examples guidelines" are followed from [our contributing
doc](https://github.com/vercel/next.js/blob/canary/contributing/examples/adding-examples.md)
In `server/render.tsx` we're switching between `react-dom/server.browser` and `react-dom/server` based on the react version users're using, unlike directly resolving them with nodejs on server side, turbopack needs to resolve both while bundling.
Bundle the ssr client layer for RSC, this solves the problem when
there's an esm package is using on client components, but esm imports
the installed react instead of the built-in react version since esm
imports is not intercepted by require hook.
After bundling the ssr client layer and treating react as externals, now
react compiles as cjs externals and could be intercepted by require
hook, other code are bundled together which can also get optimized.
## Feature
- [ ] Implements an existing feature request or RFC. Make sure the
feature request has been accepted for implementation before opening a
PR.
- [ ] Related issues linked using `fixes #number`
- [x] Integration tests added
- [ ] Documentation added
- [ ] Telemetry added. In case of a feature if it's used or not.
- [ ] Errors have a helpful link attached, see `contributing.md`
Co-authored-by: Shu Ding <g@shud.in>
Co-authored-by: JJ Kasper <jj@jjsweb.site>
Inline a react and react-dom for app dir, when `appDir` flag is enabled
opt into the built-in version for all.
For server layer react, use the react share subset for server
components.
For all server side of react-dom usage, use the server-rendering-stub.
Co-authored-by: Shu Ding <g@shud.in>
Co-authored-by: JJ Kasper <jj@jjsweb.site>
The `target: serverless` config was deprecated a year ago starting in
[Next.js 12](https://nextjs.org/blog/next-12).
Tests were disabled in #41252 so we can now remove `target: serverless`
and all usage of `target` in `next.config.js`.
Co-authored-by: Balázs Orbán <info@balazsorban.com>
Co-authored-by: JJ Kasper <jj@jjsweb.site>
Move react-dev-overlay into hot reloader client components, and let it imported by app router. So then we don't need to have hot reloader and react tree as adjacent sibilings but the overlay with error boundary is wrapping the react tree
Co-authored-by: Tim Neutkens <6324199+timneutkens@users.noreply.github.com>
This commit implements the main proposal presented in
https://github.com/vercel/next.js/issues/39241
to add attribution to web vitals.
Attribution adds more specific debugging info to web vitals,
for example in the case of Cumulative Layout Shift (CLS),
we might want to know
> What's the first element that shifted when the single largest layout shift occurred?
on in the case of Largest Contentful Paint (LCP),
> What's the element corresponding to the LCP for the page?
> If it is an image, what's the URL of the image resource?
Attribution is *disabled* by default because it could potentially
generate a lot data and overwhelm the RUM backend.
It is enabled *per metric* (LCP, FCP, CLS, etc)
As part of this change, `web-vitals` has been upgraded to v3.0.0
This version contains minor bug fixes, please see changelog at
9fe3cc02c8Fixes#39241
## Bug
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Errors have helpful link attached, see `contributing.md`
## Feature
- [x] Implements an existing feature request or RFC. Make sure the feature request has been accepted for implementation before opening a PR.
- [x] Related issues linked using `fixes #number`
- [x] Integration tests added
- [x] Documentation added
- [ ] Telemetry added. In case of a feature if it's used or not.
- [ ] Errors have helpful link attached, see `contributing.md`
## Documentation / Examples
- [ ] Make sure the linting passes by running `pnpm lint`
- [x] The examples guidelines are followed from [our contributing doc](https://github.com/vercel/next.js/blob/canary/contributing.md#adding-examples)
Co-authored-by: JJ Kasper <22380829+ijjk@users.noreply.github.com>
Re-do of https://github.com/vercel/next.js/pull/40251
Edge SSR'd routes cold boot performances are proportional to the
executed code size.
In order to improve it, we are trying to optimize for the bundle size of
a packed Edge SSR route.
This PR adds ESM compilation targets for all Next.js dist packages and
use them to bundle Edge SSR'd route.
This allows us to leverage the better tree shaking/DCE for ESM modules
in webpack in order to decrease the overall bundle size.
This PR also enables minifying Edge SSR routes. Since we don't control
which minifier might be used later (if any), it's best if we provide an
already optimised bundle.
<img width="903" alt="image"
src="https://user-images.githubusercontent.com/11064311/190005211-b7cb2c58-a56a-44b0-8ee4-fd3f603e41bd.png">
This is a 10ms cold boot win per my benchmarking script, which I'll put
in a subsequent PR.
Not done yet:
- ~~swap exported requires in `next/link` (and others) etc to point them
to the esm modules version~~
<!--
Thanks for opening a PR! Your contribution is much appreciated. In order
to make sure your PR is handled as smoothly as possible we request that
you follow the checklist sections below. Choose the right checklist for
the change that you're making: -->
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Errors have helpful link attached, see `contributing.md`
- [x] Implements an existing feature request or RFC. Make sure the
feature request has been accepted for implementation before opening a
PR.
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Documentation added
- [ ] Telemetry added. In case of a feature if it's used or not.
- [ ] Errors have helpful link attached, see `contributing.md`
- [ ] Make sure the linting passes by running `pnpm lint`
- [ ] The examples guidelines are followed from [our contributing
doc](https://github.com/vercel/next.js/blob/canary/contributing.md#adding-examples)
Co-authored-by: JJ Kasper <jj@jjsweb.site>
Co-authored-by: Shu Ding <g@shud.in>
<!--
Thanks for opening a PR! Your contribution is much appreciated.
To make sure your PR is handled as smoothly as possible we request that
you follow the checklist sections below.
Choose the right checklist for the change that you're making:
-->
## Bug
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Errors have a helpful link attached, see `contributing.md`
## Feature
- [ ] Implements an existing feature request or RFC. Make sure the
feature request has been accepted for implementation before opening a
PR.
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Documentation added
- [ ] Telemetry added. In case of a feature if it's used or not.
- [ ] Errors have a helpful link attached, see `contributing.md`
## Documentation / Examples
- [ ] Make sure the linting passes by running `pnpm lint`
- [ ] The "examples guidelines" are followed from [our contributing
doc](https://github.com/vercel/next.js/blob/canary/contributing/examples/adding-examples.md)
Co-authored-by: JJ Kasper <jj@jjsweb.site>
Co-authored-by: Shu Ding <g@shud.in>
This reverts commit 11deaaa82b.
Temporarily reverts the above commit due to breaking middleware/edge
functions once deployed.
Fixes:
https://github.com/vercel/next.js/actions/runs/3133433920/jobs/5087331787
cc @shuding @feedthejim
```sh
[GET] /blog/first
13:56:56:61
2022-09-27T20:56:56.671Z 61d43a6a-34a1-40c0-b71f-4ae5d1918431 ERROR /var/task/node_modules/next/dist/esm/client/router.js:1
/* global window */ import React from 'react';
^^^^^^
SyntaxError: Cannot use import statement outside a module
at Object.compileFunction (node:vm:352:18)
at wrapSafe (node:internal/modules/cjs/loader:1033:15)
at Module._compile (node:internal/modules/cjs/loader:1069:27)
at Object.Module._extensions..js (node:internal/modules/cjs/loader:1159:10)
at Module.load (node:internal/modules/cjs/loader:981:32)
at Function.Module._load (node:internal/modules/cjs/loader:822:12)
at Module.require (node:internal/modules/cjs/loader:1005:19)
at require (node:internal/modules/cjs/helpers:102:18)
at Object.<anonymous> (/var/task/node_modules/next/router.js:3:7)
at Module._compile (node:internal/modules/cjs/loader:1105:14)
```
This PR adds a new `experimental.enableUndici` option to let the
developer switch from `next-fetch` to `undici` as the underlying
polyfill for `fetch` in Node.js.
In the current implementation, Next.js makes sure that `fetch` is always
available by using `node-fetch`. However, we do not polyfill in Node.js
18+, since those versions come with their own `fetch` implementation
already, built-in.
Node.js 18+ uses `undici` under the hood, so letting the developer use
`undici` earlier could make the migration easier later on.
Eventually, we hope to be able to stop polyfilling `fetch` in an
upcoming major version of Next.js, shipping less code.
## Bug
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Errors have helpful link attached, see `contributing.md`
## Feature
- [ ] Implements an existing feature request or RFC. Make sure the
feature request has been accepted for implementation before opening a
PR.
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Documentation added
- [ ] Telemetry added. In case of a feature if it's used or not.
- [ ] Errors have helpful link attached, see `contributing.md`
## Documentation / Examples
- [ ] Make sure the linting passes by running `pnpm lint`
- [ ] The examples guidelines are followed from [our contributing
doc](https://github.com/vercel/next.js/blob/canary/contributing.md#adding-examples)
Co-authored-by: Balázs Orbán <info@balazsorban.com>
Co-authored-by: Sukka <isukkaw@gmail.com>
Co-authored-by: JJ Kasper <jj@jjsweb.site>
Co-authored-by: Steven <steven@ceriously.com>
# Context
Edge SSR'd routes cold boot performances are proportional to the
executed code size.
In order to improve it, we are trying to optimize for the bundle size of
a packed Edge SSR route.
This PR adds ESM compilation targets for all Next.js dist packages and
use them to bundle Edge SSR'd route.
This allows us to leverage the better tree shaking/DCE for ESM modules
in webpack in order to decrease the overall bundle size.
This PR also enables minifying Edge SSR routes. Since we don't control
which minifier might be used later (if any), it's best if we provide an
already optimised bundle.
<img width="903" alt="image"
src="https://user-images.githubusercontent.com/11064311/190005211-b7cb2c58-a56a-44b0-8ee4-fd3f603e41bd.png">
This is a 10ms cold boot win per my benchmarking script, which I'll put
in a subsequent PR.
Not done yet:
- ~~swap exported requires in `next/link` (and others) etc to point them
to the esm modules version~~
<!--
Thanks for opening a PR! Your contribution is much appreciated.
In order to make sure your PR is handled as smoothly as possible we
request that you follow the checklist sections below.
Choose the right checklist for the change that you're making:
-->
## Bug
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Errors have helpful link attached, see `contributing.md`
## Feature
- [x] Implements an existing feature request or RFC. Make sure the
feature request has been accepted for implementation before opening a
PR.
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Documentation added
- [ ] Telemetry added. In case of a feature if it's used or not.
- [ ] Errors have helpful link attached, see `contributing.md`
## Documentation / Examples
- [ ] Make sure the linting passes by running `pnpm lint`
- [ ] The examples guidelines are followed from [our contributing
doc](https://github.com/vercel/next.js/blob/canary/contributing.md#adding-examples)
Co-authored-by: JJ Kasper <jj@jjsweb.site>
Co-authored-by: Shu Ding <g@shud.in>
This is an initial implementation of the Server Components SWC
transformer. For the server graph, it detects client entries via the
`"client"` directive and transpile them into module reference code; for
the client graph, it removes the directives. And for both graphs, it
checks if there is any invalid imports for the given environment and
shows proper errors.
With that added, we can switch from `next-flight-client-loader` to
directly use the SWC loader in one pass. Next step is to get rid of the
`.client.` extension in other plugins.
## Bug
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Errors have helpful link attached, see `contributing.md`
## Feature
- [x] Implements an existing feature request or RFC. Make sure the
feature request has been accepted for implementation before opening a
PR.
- [ ] Related issues linked using `fixes #number`
- [x] Integration tests added
- [ ] Documentation added
- [ ] Telemetry added. In case of a feature if it's used or not.
- [ ] Errors have helpful link attached, see `contributing.md`
## Documentation / Examples
- [ ] Make sure the linting passes by running `pnpm lint`
- [ ] The examples guidelines are followed from [our contributing
doc](https://github.com/vercel/next.js/blob/canary/contributing.md#adding-examples)
<!--
## Bug
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Errors have helpful link attached, see `contributing.md`
## Feature
- [x] Implements an existing feature request or RFC. Make sure the
feature request has been accepted for implementation before opening a
PR.
- [ ] Related issues linked using `fixes #number`
- [x] Integration tests added
- [ ] Documentation added
- [ ] Telemetry added. In case of a feature if it's used or not.
- [ ] Errors have helpful link attached, see `contributing.md`
## Documentation / Examples
- [x] Make sure the linting passes by running `pnpm lint`
- [ ] The examples guidelines are followed from [our contributing
doc](https://github.com/vercel/next.js/blob/canary/contributing.md#adding-examples)
- [ ] -->
## Feature
- [x] Implements https://github.com/vercel/next.js/discussions/40112
- [x] Integration tests added
Adds a new option to the current font optimization to enable
experimental font size adjust
The new `optimizeFonts` config will be
```
optimizeFonts: {
inlineFonts: true,
experimentalAdjustFallbacks: false,
},
```
To enable the feature, set `experimentalAdjustFallbacks: true`
`optimizeFonts: false` will disable the entire feature (including
inlining google font definition)
Co-authored-by: JJ Kasper <jj@jjsweb.site>
The `next/config` code generated is incompatible with the `type: "module"` setting in `package.json`. This PR makes sure that we append the same interop code to the output `shared/lib/runtime-config` file as other re-exported modules:
93830bf04f/packages/next/taskfile-swc.js (L124-L128)Fixes#40159
## Bug
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Errors have helpful link attached, see `contributing.md`
## Feature
- [ ] Implements an existing feature request or RFC. Make sure the feature request has been accepted for implementation before opening a PR.
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Documentation added
- [ ] Telemetry added. In case of a feature if it's used or not.
- [ ] Errors have helpful link attached, see `contributing.md`
## Documentation / Examples
- [ ] Make sure the linting passes by running `pnpm lint`
- [ ] The examples guidelines are followed from [our contributing doc](https://github.com/vercel/next.js/blob/canary/contributing.md#adding-examples)
Typescript published 4.8.2 today and it fails CI, bump our typescript version to 4.8.2 and tweak some typings to make existing e2e typescript tests work properly
* Bump web-vitals from 3.0.0-beta to 3.0.0 stable for typing fix (there's an undefined type but it wasn't caught by ts 4.7), also force compiled it as CJS for pre-compiled
* Bump ncc to 3.34.0 for ts-loader compatibility for new typescript version, ncc 3.33.x cannot work with ts 4.8
* Update pre-compiled
As noticed by @shuding we were disabling minifying for the webpack 5 bundle which was most likely left over from debugging which isn't necessary now as we can use the local version of webpack via the NEXT_PRIVATE_LOCAL_WEBPACK5 env variable instead.
follow-up for #39518
* revert `styled-jsx/style` import path to `next/dist/shared/styled-jsx`
* Since `styled-jsx` cannot be resolved through `node_modules/next/node_modules` by external resolving, we forcedly resolve styled-jsx as cjs external in webpack
Co-authored-by: JJ Kasper <22380829+ijjk@users.noreply.github.com>
Improve styled-jsx types in next.js, previously there's no `declare module` for styled-jsx and there's type name conflicts in `styled-jsx/index.d.ts` and we use a rename hack to avoid the conflicts. Now styled-jsx 5.0.3 fixed those issues.
x-ref: https://github.com/vercel/styled-jsx/pull/805
* Use require hook and alias to resolve styled-jsx
* re-export styled-jsx types from compiled
* fix lint
* add test for styled-jsx css
* setup require hook in server
* compile import path to styled-jsx/style
* revert require hook
* add test for server styled-jsx resolving
* update test
* pre copy styled-jsx assets
* fix styled-jsx dts
* add npmrc for styled-jsx e2e test
* load require hook directly
* rm legacy test
* fix lint
* fix pnpm install error
* split require hook
* only alias styled-jsx
* make styled-jsx resolving statically analyzable
* update test
Co-authored-by: JJ Kasper <jj@jjsweb.site>
This commit allows the users to import URLPattern from `next/server`,
by defining a key that uses `global.URLPattern`.
Why is this any good? or: why don't we add URLPattern to the global namespace?
URLPattern is exposed as global on Edge Runtime _only_. This means that if we define a
constructor in global namespace in our TypeScript definitions, people might
have runtime errors in their Node.js functions.
Importing from `next/server` enables users to get the constructor without
risking in runtime errors and wrong type definitions.
Keep in mind, that with the current implementation, we do not check if the
constructor actually exists, but `next/server` shouldn't be imported in
Node.js functions, AFAIK.
## Related
- Fixes#38131
## Bug
- [x] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Errors have helpful link attached, see `contributing.md`
Co-authored-by: JJ Kasper <22380829+ijjk@users.noreply.github.com>
This PR updates the Edge Runtime to use a new version that loads dependencies differently. This addresses https://github.com/vercel/next.js/pull/38766 so `instanceof` works as expected.
It involved a few code changes, mostly regarding to types. The most important change is that the `Runner` function in the sandbox doesn't take a `ReadableStream` as `body` anymore since this implies creating the instance on "node land" and makes the runtime `fetch` function not to be able to compare with `ReadableStream` using `instanceof`. Instead we introduce a "clonable body" abstraction that allows to create the `ReadableStream` from `Readable` by using the edge runtime primitive which would hold the correct prototype.
Also, this PR changes the way we pre-compile the Edge Runtime to adapt it to the new version.
* Add next.config.js validation with ajv
* update manifest
* update lib type
* remove old tests
* update to pre-build validation code
* ensure validate output is ncced
* Apply suggestions from code review
Co-authored-by: Steven <steven@ceriously.com>
* Add example of typing next.config.js
Co-authored-by: Steven <steven@ceriously.com>
Handles the case where an error is introduced which causes a Fast Refresh and then it's fixed.
## Bug
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Errors have helpful link attached, see `contributing.md`
## Feature
- [ ] Implements an existing feature request or RFC. Make sure the feature request has been accepted for implementation before opening a PR.
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Documentation added
- [ ] Telemetry added. In case of a feature if it's used or not.
- [ ] Errors have helpful link attached, see `contributing.md`
## Documentation / Examples
- [ ] Make sure the linting passes by running `pnpm lint`
- [ ] The examples guidelines are followed from [our contributing doc](https://github.com/vercel/next.js/blob/canary/contributing.md#adding-examples)
## Bug
- [x] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Errors have helpful link attached, see `contributing.md`
Fixes#38106.
Currently, the `shared/lib` directory (**which will also be shipped to legacy browsers**) is precompiled under `swcServerOptions`, which targets Node.js 12 and is way too modern:
- The public class field syntax is only supported since Chrome 72, Firefox 69, Edge 79, and Safari 14.1.
- Webpack currently doesn't support the public class field syntax as well (which causes the issue #38106)
- `async/await` syntax is also supported in Node.js 12 but not in the legacy browsers.
The PR fixes the issue by pre-compiling the `shared/lib` directory using `swcClientOptions` (which targets the ES5).
Note:
- The only way to validate the fix is to run an integration test case on a legacy browser.
- The output size is increased by a little. But the size impact can be minimized by enabling `@swc/helpers` (which I will bring up in the next PR)
This ensures we expose the `styled-jsx` types correctly even when the package is not hoisted from next's `node_modules` e.g. when using `pnpm`. We had an existing test that covered this although it installed `styled-jsx` at the top-level as a workaround so the test has been updated to remove this workaround.
## Bug
- [x] Related issues linked using `fixes #number`
- [x] Integration tests added
- [ ] Errors have helpful link attached, see `contributing.md`
Fixes: https://github.com/vercel/next.js/pull/37828#discussion_r901164193
This PR introduces [Edge Runtime](https://edge-runtime.vercel.app/) for emulating [Edge Functions](https://vercel.com/features/edge-functions) locally.
Every time you run a [middleware](https://nextjs.org/docs/advanced-features/middleware) locally via `next dev`, an isolated edge runtime context will be created.
These contexts have the same constraints as production servers, plus they don't pollute the global scope; Instead, all the code run in a vm on top of a Node.js process.
Additionally, `@edge-runtime/jest-environment` has been added to make easier testing Edge Functions in a programmatic way.
It dropped the following polyfills from Next.js codebase, since they are now part of Edge Runtime:
- abort-controller
- formdata
- uuid
- web-crypto
- web-streams
Co-authored-by: Gal Schlezinger <2054772+Schniz@users.noreply.github.com>
Another strategy to do achieve the goal of #36995. With this PR the module IDs will be:
- (1) RSC: named (_this one doesn't matter_)
- (2) SSR: named
- (3) Client: deterministic
And we include the client module IDs in the flight manifest, as well as an extra mapping of 3) → 2) so during SSR it can require the correct module still.
## Bug
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Errors have helpful link attached, see `contributing.md`
## Feature
- [ ] Implements an existing feature request or RFC. Make sure the feature request has been accepted for implementation before opening a PR.
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Documentation added
- [ ] Telemetry added. In case of a feature if it's used or not.
- [ ] Errors have helpful link attached, see `contributing.md`
## Documentation / Examples
- [ ] Make sure the linting passes by running `yarn lint`
- [ ] The examples guidelines are followed from [our contributing doc](https://github.com/vercel/next.js/blob/canary/contributing.md#adding-examples)
Follow-up PR for #37134, this PR adds back the hash in each chunk's filename. This `chunks` in the flight manifest will now be `chunkId:chunkFilename` with this PR, and `globalThis.__next_chunk_load__` then handles the chunk registration (uses chunkId) and chunk loading (uses chunkFilename). (Q: how can we port this to React?)
We can't use `[contenthash]` but only `[chunkhash]` because at the stage of generating the flight manifest, the content isn't finalized and the hash changes after that.
## Bug
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Errors have helpful link attached, see `contributing.md`
## Feature
- [ ] Implements an existing feature request or RFC. Make sure the feature request has been accepted for implementation before opening a PR.
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
- [ ] Documentation added
- [ ] Telemetry added. In case of a feature if it's used or not.
- [ ] Errors have helpful link attached, see `contributing.md`
## Documentation / Examples
- [ ] Make sure the linting passes by running `yarn lint`
Adds the `hmr/hotModuleReplacement.js` file to the compiled output
that is used in
`packages/next/build/webpack/plugins/mini-css-extract-plugin.ts`.
Fixes#25560
## Bug
- [x] Related issues linked using `fixes #number`
- [ ] Integration tests added
Co-authored-by: JJ Kasper <22380829+ijjk@users.noreply.github.com>
We added custom _app as server component support in #33149, but we found it's pretty confusing on usage like support it both server component pages and regular pages at the same time for having similar layout purpose.
When using the _app.server and _app at the same time, applying them into proper places become more confusing.
In that case, we decide to make _app.js can't be a server component, and you can still keep all the existing thing there. And also you don't need to think of the corresponding APIs of custom _app in RSC
- [ ] Related issues linked using `fixes #number`
- [x] Integration tests added
- [x] Docs updated