Use `Writable` instead of `Observable` and remove the `zen-observable` dependencies. I initially opted to use `Observable` for simplicity and fast iteration, but we should really just use `Writable` directly (or some other stream in the future).
React's streaming SSR has some [specific requirements](https://github.com/reactwg/react-18/discussions/66#discussioncomment-944266) on the stream API. Rather than trying to also squeeze a `Readable` in here, which might be more standard for node apps, I've just followed React's lead. By limiting ourselves to just `Writable`, it ought to be easier to adopt a different stream type in the future if desired.
The React `pipeToNodeWritable` API requires us to pass a stream immediately, but we don't actually have a `ServerResponse` to give it until `RenderResult.pipe(...)` is called later. For that reason, we pass React a `Writable` that we will simply forward to `res` later. This mechanism of deferring is `NodeWritablePiper`, which is just a function that can be called with `ServerResponse` (or another `Writable`, as we now do to render to string for static results) to have content written to it. `NodeWritablePiper` takes a `next` argument so that we can chain both synchronous and asynchronous pipers together.
Also does some clean up and adds another streaming test for backpressure.
This updates our `jest` configuration to no longer use `babel-jest` and instead uses `@swc/jest` which is much faster. This also updates to the latest version of `jest`, fixes our `tsconfig.json` used for tests (previously types in `node_modules` weren't resolved correctly), and ensures `next/dist` isn't un-necessarily transpiled in `jest`.
Timings for `yarn testheadless test/unit/` on CI
- before: 3m 30s - 4m ([example run](https://github.com/vercel/next.js/runs/3394701995))
- after: under 1m ([example run](https://github.com/vercel/next.js/pull/28400/checks?check_run_id=3395161621))
Timings for `yarn testheadless test/unit/` locally on m1 mac
- before: 90.16 seconds
- after: 29.92 seconds
Our `Observable` use has gotten sufficiently complex that it makes sense to just use a 3rd party implementation and not worry about maintaining it ourselves. As a bonus, it doesn't rely on Node APIs.
This PR introduces an improved developer experience when `next lint` is run for the first time.
### Current behavior
`eslint-config-next` is a required package that must be installed before proceeding with `next lint` or `next build`:
![image](https://user-images.githubusercontent.com/12476932/123468791-43088100-d5c0-11eb-9ad0-5beb80b6c968.png)
Although this has helped many developers start using the new ESLint config, this has also resulted in a few issues:
- Users are required to install the full config (`eslint-config-next`) even if they do not use it or use the Next.js plugin directly (`eslint-plugin-next`).
- #26348
- There's some confusion on why `eslint-config-next` needs to be installed or how it should be used instead of `eslint-plugin-next`.
- #26574
- #26475
- #26438
### New behavior
Instead of enforcing `eslint-config-next` as a required package, this PR prompts the user by asking what config they would like to start. This happens when `next lint` is run for the first time **and** if no ESLint configuration is detected in the application.
<img src="https://user-images.githubusercontent.com/12476932/124331177-e1668a80-db5c-11eb-8915-38d3dc20f5d4.gif" width="800" />
- The CLI will take care of installing `eslint` or `eslint-config-next` if either is not already installed
- Users now have the option to choose between a strict configuration (`next/core-web-vitals`) or just the base configuration (`next`)
- For users that decide to create their own ESLint configuration, or already have an existing one, **installing `eslint-config-next` will not be a requirement for `next lint` or `next build` to run**. A warning message will just show if the Next.js ESLint plugin is not detected in an ESLint config.
<img width="682" alt="Screen Shot 2021-06-25 at 3 02 12 PM" src="https://user-images.githubusercontent.com/12476932/123473329-6cc4a680-d5c6-11eb-9a57-d5c0b89a2732.png">
---
In addition, this PR also:
- Fixes#26348
- Updates documentation to make it more clear what approach to take for new and existing ESLint configurations
Fixes#27593
## Bug
- [x] 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
I'm not sure if this is something that y'all want but it `web-vitals` has been integrating more browser support. The major release is because they removed the [`isFinal` flag on the Metric type](d233b7b8c3).
add `experimental.esmExternals: boolean | 'loose'` config option
remove `output.environment` configuration in favor of `target`
| | `esmExternals: false` (default) | `esmExternals: 'loose'` | `esmExternals: true` |
| ------------------------ | ------------------------------- | ----------------------- | -------------------- |
| import cjs package | `require()` | `require()` | `require()` |
| require cjs package | `require()` | `require()` | `require()` |
| import mixed package | `require()` *** | `import()` | `import()` |
| require mixed package | `require()` | `require()` | `require()` |
| import pure esm package | `import()` | `import()` | `import()` |
| require pure esm package | Error ** | `import()` * | Error ** |
| import pure cjs package | `require()` | `require()` | Resolving error |
| require pure cjs package | `require()` | `require()` | `require()` |
cjs package: Offers only CJS implementation (may not even have an `exports` field)
mixed package: Offers CJS and ESM implementation via `exports` field
pure esm package: Only offers an ESM implementation (may not even have an `exports` field)
pure cjs package: CommonJs package that prevents importing via `exports` field when `import` is used.
`*` This case will behave a bit unexpected for now, since `require` will return a Promise. So that need to be awaited. This will be fixed once the whole next.js bundle is ESM. It didn't work at all before this PR.
`**` This is a new Error when trying to require an esm package.
`***` For mixed packages we prefer the CommonJS variant to avoid a breaking change.
## 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.
- [x] Errors have helpful link attached, see `contributing.md`
## Documentation / Examples
- [ ] Make sure the linting passes
This Pull Request adds [Alex](https://alexjs.com/) to our documentation. It catches insensitive, inconsiderate writing.
The original PR (https://github.com/vercel/next.js/pull/25821) is too large so I have decided to break it down into smaller PRs. This PR is the first part. Then I will continue to add the rest of the documentation in smaller PRs.
## More Information on Alex:
https://alexjs.com/https://github.com/get-alex/alex
## Documentation / Examples
- [x] Make sure the linting passes
This PR does a couple things:
1. Omit svg static imports if the user has defined custom webpack config with svg rule
2. Change TS type to `any` for svg imports to avoid conflicts with other plugins
The idea is that some users want to use `next/image` with static imports for most image types but not for svg and instead inline those images with a plugin.
- Fixes#25950
- Fixes#26130
- Fixes#26176
- Fixes#26196
- Fixes#26067
## Bug
- [x] Related issues linked using Fixes#26130
- [x] Integration tests added
This updates to the latest version of webpack 5 which includes a fix waiting on certain webpack assets
## Bug
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
## 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.
## Documentation / Examples
- [ ] Make sure the linting passes
## 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.
This pull request upgrades `postcss-loader` from `4.0.3` to `4.3.0`. Version `4.3.0` [adds support](https://github.com/webpack-contrib/postcss-loader/pull/525) for the `dir-dependency` message type which PostCSS plugins can use to register directories as dependencies ([documentation](https://github.com/postcss/postcss/blob/main/docs/guidelines/plugin.md#31-use-messages-to-specify-dependencies)).
## Bug
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
## 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.
## Documentation / Examples
- [ ] Make sure the linting passes
fixes a small bug which caused the webpack chunk to be too big as it includes references to all pages
## Bug
- [x] Related issues linked using `fixes #number`
- [ ] Integration tests added
## 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.
## Documentation / Examples
- [ ] Make sure the linting passes
* update webpack to 5.36.2
* use dependOn to optimize chunks
* disable vendor splitting for main and _app chunks
=> decreases bundle size in general, gets rid of the 2 extra vendor chunks shared by all pages.
## Bug
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
## 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.
## Documentation / Examples
- [ ] Make sure the linting passes
This PR re-includes ESLint with some notable changes, namely a guided setup similar to how TypeScript is instantiated in a Next.js application.
To add ESLint to a project, developers will have to create an `.eslintrc` file in the root of their project or add an empty `eslintConfig` object to their `package.json` file.
```js
touch .eslintrc
```
Then running `next build` will show instructions to install the required packages needed:
<img width="862" alt="Screen Shot 2021-04-19 at 7 38 27 PM" src="https://user-images.githubusercontent.com/12476932/115316182-dfd51b00-a146-11eb-830c-90bad20ed151.png">
Once installed and `next build` is run again, `.eslintrc` will be automatically configured to include the default config:
```json
{
"extends": "next"
}
```
In addition to this change:
- The feature is now under the experimental flag and requires opt-in. After testing and feedback, it will be switched to the top-level namespace and turned on by default.
- A new ESLint shareable configuration package is included that can be extended in any application with `{ extends: 'next' }`
- This default config extends recommended rule sets from [`eslint-plugin-react`](https://www.npmjs.com/package/eslint-plugin-react), [`eslint-plugin-react-hooks`](https://www.npmjs.com/package/eslint-plugin-react-hooks), and [`eslint-plugin-next`](https://www.npmjs.com/package/@next/eslint-plugin-next)
- All rules in [`eslint-plugin-next`](https://www.npmjs.com/package/@next/eslint-plugin-next) have been modified to include actionable links that show more information to help resolve each issue
Fixes#24421
## Bug
- [x] Related issues linked using `fixes #number`
- [ ] Integration tests added
Can't add an integration test currently, we'll add Node 16 tests later.
## 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.
## Documentation / Examples
- [ ] Make sure the linting passes
## Bug
- [ ] Related issues linked using `fixes #number`
- [ ] Integration tests added
## 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.
## Documentation / Examples
- [ ] Make sure the linting passes