Closes#40775
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## 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)
This PR updates the docs and examples for `create-next-app` to include pnpm usage.
The following script was used to update every example README:
```js
const fs = require('fs')
const examples = fs.readdirSync('./examples')
for (let example of examples) {
const filename = `./examples/${example}/README.md`
const markdown = fs.readFileSync(filename, 'utf8')
const regex = new RegExp(`^yarn create next-app --example (.*)$`, 'gm')
const output = markdown.replace(regex, (yarn, group) => {
const pnpm = `pnpm create next-app -- --example ${group}`
return `${yarn}\n# or\n${pnpm}`
})
fs.writeFileSync(filename, output)
}
```
Clean up package.json files in the `examples` directory:
- Add `private: true`
- Remove `version` (because they are irrelevant for packages that are not meant to be published)
- Remove `name` (because they are optional for packages that are not meant to be published, and when someone clones an example, they often rename it and the property becomes stale)
- Remove `author`
- Remove `description`
- Remove `license`
Also remove `with-dynamic-app-layout` example completely, since it does the same as `layout-component` (https://github.com/vercel/next.js/pull/27121#discussion_r668178408).
## Documentation / Examples
- [x] Make sure the linting passes
[With next 11 requiring react 17](https://nextjs.org/blog/next-11#upgrade-guide), most of the examples
need to be updated, so the following snippet updated all the examples to
a compatible react version.
```bash
cd examples/
fd -g 'package.json' | xargs sed -r -i 's/"react": ".*"/"react": "^17.0.2"/
fd -g 'package.json' | xargs sed -r -i 's/"react-dom": ".*"/"react-dom": "^17.0.2"/'
# exclude experimental react version
git checkout with-reason-relay/package.json
```
## Changes
- Removes `mockServiceWorker.js` file and ignores it from Git. New versions of `msw` generate the worker script automatically at the location specified in `packageJson.msw.workerDirectory`. This keeps the worker script up-to-date with the currently installed version of `msw`.
- Updates `msw` package to the latest version for new features and stability improvements.
## Documentation / Examples
- [ ] Make sure the linting passes
When using the `with-msw` example I noticed it increased my bundle size in production, even through MSW is meant to be used in development only.
**Build size before implementing MSW**
```
Page Size First Load JS
┌ λ / 479 B 58.9 kB
├ /_app 0 B 58.4 kB
└ ○ /404 3.44 kB 61.9 kB
+ First Load JS shared by all 58.4 kB
├ chunks/f6078781a05fe1bcb0902d23dbbb2662c8d200b3.b1b405.js 10.3 kB
├ chunks/framework.cb05d5.js 39.9 kB
├ chunks/main.a140d5.js 7.28 kB
├ chunks/pages/_app.b90a57.js 277 B
└ chunks/webpack.e06743.js 751 B
λ (Server) server-side renders at runtime (uses getInitialProps or getServerSideProps)
○ (Static) automatically rendered as static HTML (uses no initial props)
● (SSG) automatically generated as static HTML + JSON (uses getStaticProps)
(ISR) incremental static regeneration (uses revalidate in getStaticProps)
```
**Build size after implementing MSW according to the `with-msw` example**
```
Page Size First Load JS
┌ λ / 479 B 71.6 kB
├ /_app 0 B 71.1 kB
└ ○ /404 3.44 kB 74.6 kB
+ First Load JS shared by all 71.1 kB
├ chunks/f6078781a05fe1bcb0902d23dbbb2662c8d200b3.b1b405.js 10.3 kB
├ chunks/framework.cb05d5.js 39.9 kB
├ chunks/main.a140d5.js 7.28 kB
├ chunks/pages/_app.c58a6f.js 13 kB
└ chunks/webpack.e06743.js 751 B
λ (Server) server-side renders at runtime (uses getInitialProps or getServerSideProps)
○ (Static) automatically rendered as static HTML (uses no initial props)
● (SSG) automatically generated as static HTML + JSON (uses getStaticProps)
(ISR) incremental static regeneration (uses revalidate in getStaticProps)
```
There was a 12.7 kB large increase in the `_app` First Load JS which increased the pages' First Load JS size. I tracked the problem down to the following code:
```js
if (process.env.NEXT_PUBLIC_API_MOCKING === 'enabled') {
require('../mocks')
}
```
Removing this reduces the `_app` First Load JS to what it was previously. The `NEXT_PUBLIC_API_MOCKING` environment variable is defined in the `.env.development` file, as this means that Next.js will only activate MSW during development/testing, which is what MSW is intended for.
After discussing with @kettanaito, the author of MSW, I did some investigation. This dynamic require statement is intended to allow tree-shaking of the MSW package for production. Unfortunately this did not seem to be working. To fix this, I changed the code to the following:
```js
if (process.env.NODE_ENV !== 'production') {
require('../mocks')
}
```
This means I could remove the `NEXT_PUBLIC_API_MOCKING` environment variable from `.env.development`, as it is no longer used.
It is important to note that this still achieves the same functionality as before: MSW runs in development / testing, and not in production. If MSW must be enabled in production for some reason, the following code can be used to run MSW regardless of the environment:
```js
if (true) {
require('../mocks')
}
```
If possible, I'd love to hear from the Next.js maintainers regarding the tree-shaking process when using environment variables.
Lastly, I made the necessary changes to have the example work in production mode as well, because there is no real backend. Of course there is a comment explaining what should be changed in a real world app.
