Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/47670
Now that we have `babel-plugin-syntax-hermes-parser` in `react-native/babel-preset` (since D63535216), it's no longer necessary to use `hermes-parser` directly in Metro in order to use newer Flow syntax.
Babel with `babel-plugin-syntax-hermes-parser` is generally preferable, because it intelligently falls back to parsing with Babel for any non-`flow` files.
See https://github.com/facebook/hermes/issues/1549 for context.
Changelog:
[General][Fixed] metro-config: Don't use `hermes-parser` by default, prefer `babel-plugin-syntax-hermes-parser`, which supports other syntax plugins.
Reviewed By: huntie
Differential Revision: D66002056
fbshipit-source-id: cf48acec347e2c0791872f8ca4b53f5f8af1c783
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/47109
Fixes the `lint/sort-imports` errors that are now surfaced after fixing the lint configuration.
For a couple files, I added lint suppressions instead because the unsorted import ordering is important due to interleaved calls with side effects.
Changelog:
[Internal]
Reviewed By: GijsWeterings
Differential Revision: D64569485
fbshipit-source-id: 26415d792e2b9efe08c05d1436f723faae549882
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/47012
Update Metro from `0.81.0-alpha.2` to `0.81.0`.
This is also intended to be the final, stable release for RN 0.76.
Changelog:
[General][Changed]: Update Metro to 0.81.0
Reviewed By: blakef
Differential Revision: D64329574
fbshipit-source-id: e12bed356b46e4ed68c75b397b7f9e2228c377be
Summary:
React Native [app template provided by the CLI](https://github.com/react-native-community/template) currently uses [`metro-config` directly for `MetroConfig` type](https://github.com/react-native-community/template/blob/main/template/metro.config.js#L7).
However, it doesn't have `metro-config` as neither a dependency or dev dependency, which can lead to version mismatches.
While this is obviously a mistake on the template repo side, `metro-config` versions aren't matched with `react-native` versions. Therefore, getting the correct version of `metro-config` from `react-native/metro-config` would require reflecting on `react-native/metro-config`'s package.json etc. which is far from ideal. In my opinion it's would be much better to expose `MetroConfig` type from `react-native/metro-config` directly.
Version mismatching can happen in a monorepo setup. Say we have the monorepo structure using Yarn Modern:
```tree
.
├── RN75-app (workspace)
├── RN76-app (workspace)
│ ├── metro.config.js
│ └── node_modules
│ └── react-native
│ └── metro-config (0.76)
│ └── node_modules
│ └── metro-config (version for 0.76)
└── node_modules
├── react-native
│ └── metro-config (0.75)
└── metro-config (version for 0.75)
```
`react-native@0.75` gets hoisted to the monorepo root while `react-native@0.76` sits in an RN 0.76 app workspace.
Say we have the following `RN76-app/metro.config.js` contents:
```js
const {getDefaultConfig, mergeConfig} = require('react-native/metro-config');
/**
* Metro configuration
* https://reactnative.dev/docs/metro
*
* type {import('metro-config').MetroConfig}
*/
const config = {};
module.exports = mergeConfig(getDefaultConfig(__dirname), config);
```
In this case, `require('react-native/metro-config')` would resolve to `RN76-app/node_modules/react-native/node_modules/metro-config` since `react-native/metro-config` is a (dev) dependency of the App.
However `import('metro-config).MetroConfig` would resolve to `node_modules/metro-config` since it's not a direct dependency.
This is how we have a mismatch - imported functions come from different packages than imported type.
## Changelog:
[GENERAL] [ADDED] - Expose `MetroConfig` type directly from `react-native/metro-config`.
Pull Request resolved: https://github.com/facebook/react-native/pull/46602
Test Plan:
`yarn build` to generate dist for `react-native/metro-config`, see it has the export of `MetroConfig`.
## Notes
If this PR gets approved, I'll submit relevant one to the CLI template.
Reviewed By: huntie
Differential Revision: D63258881
Pulled By: robhogan
fbshipit-source-id: e6f3c880eb4a0aa902c62932d58f243c38b07c2e
Summary:
This change bumps the React Native version in main to 0.77
bypass-github-export-checks
## Changelog:
[General][Changed] - Bump main to 0.77-main
## Facebook:
generated by running `js1 publish react-native 0.77.0-main`
Reviewed By: cortinico
Differential Revision: D62575939
fbshipit-source-id: 6d239fca2eed6cfe51f8c37f78d8dc8730c18b8c
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/46398
Bump Metro packages to the version stablising for RN 0.76
Changelog:
[General][Changed] - Bump Metro dependencies to 0.81.0-alpha.0
Reviewed By: cortinico
Differential Revision: D62377929
fbshipit-source-id: 0808b11ad534e6a649c28f32b19f95f691645be4
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/46318
Configures the Metro by default to use the Hermes parser so that React Native can fully leverage all modern Flow language syntax.
NOTE: This does not affect `*.ts` and `*.tsx` files which will continue to use Babel. Metro has logic to enforce this regardless of the transform options.
Changelog:
[General][Changed] - Changed Metro default config to use Hermes parser, enabling the use of advanced Flow syntax in React Native.
Reviewed By: robhogan
Differential Revision: D62161923
fbshipit-source-id: 0f4c069d429517be16abcc6a2187cd23c6bd52d4
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/46264
React-native was not in sync with metro changes that RN relies on
Changelog: [Internal]
Reviewed By: robhogan
Differential Revision: D61982240
fbshipit-source-id: 63b1f53174ab0ec663a537569a032c62c431eb83
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/45982
Changelog: [Internal]
Recently `src/private/renderer/errorhandling/ErrorHandlers.js` started showing up in some error stack traces, making LogBox less readable. This diff ensures we collapse these extra stack frames by default (as well as hide them in Fusebox, etc).
Reviewed By: hoxyq
Differential Revision: D61128294
fbshipit-source-id: 2ebcb47265aaf3281b669ed022c29978167f3e81
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/44362
Packages that are built and directly run in the monorepo no longer need to worry about
conditionally registering themselves to transpile Flow -> JS at runtime. Our build step
strips this file now.
Changelog: [Internal] changes in published packages no longer require conditional calls to Babel register.
Reviewed By: huntie
Differential Revision: D56839521
fbshipit-source-id: 6bec706c639f1ab4138e0b790be8a07654333046
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/44339
We require the wrapper code for in repository calls to these packages directly from node (i.e. using CommonJS). This wrapper code typically sits at the entrypoint of the build packages (i.e. `index.js`).
NOTE: This unblocks an issue preventing me from landing further work on the `helloworld` cli replacing the community template.
## Problem:
The [flow-api-translator](https://www.npmjs.com/package/flow-api-translator) library doesn't allow CommonJS `module.exports` when generating TypeScript Type Defintions.
## Change
1. At the built time, this strips out our wrapper code and sets up the dist/ folder appropriately for npm distribution.
2. Updated the `package.json` files to consistently share Flow types
Changelog: [Internal] refactor build packages output to remove wrapper.
NOTE: Added better error messages when users deviated from the current pattern:
{F1501571608}
Reviewed By: huntie
Differential Revision: D56762162
fbshipit-source-id: f110b31e4ad780998dbc81a2482891ac8d8c6458
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/43604
Changelog: [Internal]
Syncs the internal and OSS versions of `INTERNAL_CALLSITES_REGEX` in the default RN Metro config.
Reviewed By: robhogan
Differential Revision: D55237394
fbshipit-source-id: 8986a69f8beeafccbab3548d8a2137c0bf19e0b3
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/43605
Changelog: [Internal]
Leverages https://developer.chrome.com/docs/devtools/x-google-ignore-list to mark more internal files as "third party", thus collapsing them by default in stack traces in modern versions of Chrome DevTools. The list of modules to collapse is the same one used by LogBox.
This likely only affects Meta usage, since Metro's default for [`isThirdPartyModule`](https://metrobundler.dev/docs/configuration/#isthirdpartymodule) already excludes all `node_modules`, but I'm making this change across Meta and OSS for consistency and to signal intent.
Reviewed By: huntie
Differential Revision: D55236653
fbshipit-source-id: d777ea31fb3d65608a487247924885c887ebbd94
Summary:
Minor fix to package.json which newer version of npm warn about when publishing, after running `npm pkg fix -ws` on the workspace.
{F1470070110}
## Changelog: [Internal] npm pkg fix -ws
Pull Request resolved: https://github.com/facebook/react-native/pull/43519
Test Plan: eyescloseddog
Reviewed By: cortinico
Differential Revision: D55012872
Pulled By: blakef
fbshipit-source-id: ff3c63a3eefaf56d369219a3d4b32d44d6d842c9
Summary:
This adds `react-native/metro-config` to the monorepo build tool and emits the missing typescript declarations.
Right now, we do have typescript declarations on `metro-config`, but not `react-native/metro-config`. Which makes everything a bit harder extend from "[the default React Native metro config](https://github.com/facebook/react-native/pull/36502)" in Expo.
> Note, I also added the same `exports` block from `react-native/dev-middleware` for conformity.
One open question here is, why aren't we exporting _all_ helper functions from `metro-config`? To me, its a bit weird that we need both `metro-config` _and_ `react-native/metro-config` as `loadConfig` isn't exported.
## Changelog:
[INTERNAL] [FIXED] - Emit typescript declaration files for `react-native/metro-config`
Pull Request resolved: https://github.com/facebook/react-native/pull/41836
Test Plan:
Run the build tool, and check if the typescript declarations are emitted for `react-native/metro-config`.
```
yarn build metro-config
```
Reviewed By: hoxyq
Differential Revision: D51943453
Pulled By: huntie
fbshipit-source-id: cfaffe5660053fc9a9fcbe3dacf7f6ccc2bde01b
Summary:
Over in React Native macOS land, I opened https://github.com/microsoft/react-native-macos/pull/2030 to update our mono repo to use Yarn 4. As a side effect, all the `package.json` files are formatted as a side effect of running `yarn install`. So that React Native macOS doesn't maintain this diff (and because they should only be good / no harm), let's upstream the formatting changes.
## Changelog:
[INTERNAL] [CHANGED] - Format package.json files in the monorepo
Pull Request resolved: https://github.com/facebook/react-native/pull/42256
Test Plan: This change should be a no-op, CI should pass.
Reviewed By: cortinico
Differential Revision: D52727623
Pulled By: huntie
fbshipit-source-id: 67862b16d576b0903abd91e016d7add4c19853dc
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/42086
Changelog: [General][Changed] - Update monorepo dependency versions to remove ^
This change will remove the caret for now as we already perform an "align" step everytime we bump a monorepo library. This prevents monorepo library updates to affect existing releases.
The "align" step updates all monorepo libraries to use the updated bumped version: https://fburl.com/code/xfistiph
Reviewed By: huntie
Differential Revision: D52440454
fbshipit-source-id: ff071032f04bc554903dde153c594991163dfe2f
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/41219
Bump to the latest Metro release. This includes minor breaking changes to Metro subpackages that should *not* be visible to RN users.
Metro release notes: https://github.com/facebook/metro/releases/tag/v0.80.0
## Moving to unpinned versioning
Metro is a multi-package project, and not pinning to an exact version means multiple versions of `metro*` packages may appear in an RN project.
This isn't unusual in the NPM ecosystem and *shouldn't* be a problem, but historically has caused issues (eg https://github.com/facebook/react-native/issues/34714, https://github.com/facebook/metro/issues/1017). The root cause of all of these issues, as far as we know, was fixed in https://github.com/facebook/metro/commit/6d46078e74ae9a43aa90bed46dbd6610e2696cd0, a bug where Node hierarchical resolution was effectively sidestepped via a relative worker path, resulting in a mismatch between transformer and host process.
In addition, the fact that `react-refresh`, `metro-react-native-babel-transformer` and `metro-react-native-babel-preset` are now fully moved into the `react-native/` scope and versioned with React Native means there are no circular dependencies between React Native and Metro, explicit or implicit, and we're much more clearly decoupled.
So, we're moving to caret versioning to allow React Native users to pick up Metro fixes and features without requiring React Native releases and user upgrades.
Changelog:
[General][Changed] - Update Metro to ^v0.80.0, stop pinning to an exact version
Reviewed By: GijsWeterings
Differential Revision: D50731999
fbshipit-source-id: 57b07bf73c0b31f392c4d36376ca48b48a8bd598
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/39273
Upgrade Metro dependencies to 0.79.1 in `react-native`
This includes Metro breaking changes for disabling global package resolution by default and adds features like: Haste packages, enable resolution through symlinks and passing custom customTransformOptions and customResolverOptions to bundle_build_started log event so as to refine the bundling message. It also fixes arbitrary transformation of Babel plugins during registration in `metro-babel-register` and fixes "unexpected null" crash when handling a batch of file changes and symlinks with indirections.
**Full Metro Changelog:** https://github.com/facebook/metro/releases/tag/v0.79.1https://github.com/facebook/metro/releases/tag/v0.79.0
Changelog:
[General][Changed] Upgraded Metro to 0.79.1
Reviewed By: motiz88, mdvacca
Differential Revision: D48922815
fbshipit-source-id: 37aea6194fe587e0d094c96ceec1122c588f0fbb
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/38988
- Upgrade to RN CLI `12.0.0-alpha.9`, including Metro bump to `0.78.0`.
- Update test scripts, since this CLI release made a breaking change to the `/status` response.
Changelog: [Internal]
Reviewed By: cortinico
Differential Revision: D48311214
fbshipit-source-id: bb0be3c32edb629355b9fbbd754b28f9878f47ef
Summary:
X-link: https://github.com/facebook/metro/pull/1024
Pull Request resolved: https://github.com/facebook/react-native/pull/38228
Changelog: [General][Changed] - Move react-native-babel-transformer and react-native-babel-preset from Metro to React Native repo.
Metro Changelog: **[Breaking]** - Remove `metro-react-native-babel-transformer` and `metro-react-native-babel-preset`, to be published as `react-native/metro-babel-transformer` and `react-native/babel-preset` instead.
This diff does the following:
- Move `metro/packages/metro-react-native-babel-preset` to `react-native/packages/react-native-babel-preset`.
- Rename `metro-react-native-babel-preset` package to `react-native/babel-preset`.
- Move `metro/packages/metro-react-native-babel-transformer` to `react-native/packages/react-native-babel-transformer`.
- Rename `metro-react-native-babel-transformer` package to `react-native/metro-babel-transformer`.
- Upadate dependencies.
Reviewed By: robhogan
Differential Revision: D46977466
fbshipit-source-id: 32478f63a0442b61a1804f12ef814c8b29d7f8bb
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/38554
@public
Upgrades React Native, Relay, and Metro to use `hermes-parser@0.14.0`.
This also changes the repository's Jest configuration to now use `hermes-parser`.
Changelog:
[Internal]
Reviewed By: SamChou19815
Differential Revision: D47522140
fbshipit-source-id: 207ccd0c4e4489d486731d0c847d8089abc1cc72
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/38217
Marks more filename patterns as "internal call sites" which has the effect of collapsing them by default in LogBox (and skipping them for the purpose of providing a code frame).
Changelog: [General][Fixed] Hide Babel helpers and other core files from LogBox stack traces by default
Reviewed By: cortinico, huntie
Differential Revision: D47230876
fbshipit-source-id: fe2d59d975c61cbdfd7b8da42288e284f3ab0739
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/38141
Bump CLI and Metro versions on main to latest.
Changelog:
[General][Fixed] - Bump CLI to 12.0.0-alpha.6, Metro to 0.76.7
Reviewed By: dmytrorykun
Differential Revision: D47153654
fbshipit-source-id: d9eff64e5539f0e577e059bce836af3c65a4a8c7
Summary:
This diff adds _missing_ README files for all public RN packages.
#### Changes:
For all public RN packages:
- Add _Missing_ READMEs
Update package.json in all RN packages to add:
- Issues, Bugs urls
- Keywords and Homepage urls to respective pkgs
## Changelog:
[GENERAL][ADDED] - Add missing README files for all public RN packages.
[GENERAL][CHANGED] - Update package.json in all RN packages to add required fields.
Pull Request resolved: https://github.com/facebook/react-native/pull/37090
Test Plan: - `yarn lint && yarn flow && yarn test-ci` --> _should be green_
Reviewed By: cortinico
Differential Revision: D45390861
Pulled By: hoxyq
fbshipit-source-id: 524a92de56a7cb553573d9f54ccf40a998dfd35f
Summary:
**NOTE**: This is a **BREAKING** change.
TLDR; Enforce minimum Node.js v16 in all RN packages.
This diff **Updates Node.js to v16** across all RN packages.
#### Context:
- For RN development and new project created; bump to node 16 was in https://github.com/facebook/react-native/pull/36217
- Recently `react-native-windows` also; updated node to v16, https://github.com/microsoft/react-native-windows/pull/11500
#### Changes:
- [BREAKING] Update Node.js to v16 across all RN packages under 'packages/' dir
## Changelog:
[GENERAL][BREAKING] - Update Node.js to v16 in all RN packages
Pull Request resolved: https://github.com/facebook/react-native/pull/37073
Test Plan: - `yarn lint && yarn flow && yarn test-ci` --> _should be green_
Reviewed By: cipolleschi
Differential Revision: D45306108
Pulled By: jacdebug
fbshipit-source-id: e3ba7d0151b86a6a0a3d63fb29c2bd887e1ac1e7
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/36777
Changelog: [Internal]
Remove internal merge of `getDefaultConfig` (Metro base defaults) from `react-native/metro-config`. This is unnecessary given the config loading setup of RN CLI and Expo CLI, which use (or replicate) Metro's [`loadConfig`](https://github.com/facebook/metro/blob/1e47cb5b3cc289530fb18e402891f9d2816611dd/packages/metro-config/src/loadConfig.js#L182-L190) function — which will itself apply defaults appropriately.
This relates to a previously-breaking behaviour documented in the test plan of https://github.com/react-native-community/cli/pull/1896 (independently fixed and no longer load-bearing) (**read: no need to cherry pick this change**).
https://pxl.cl/2B8NS
While this has no effect under the fixed RN CLI setup, this is a worthwhile simplification to this package that better-aligns with current Metro tooling expectations.
## Notes
- `getDefaultConfig` no longer returns `ConfigT` (full config), and instead returns `MetroConfig` (partial config). This is non-breaking with the expected API of a given `metro.config.js` file.
Reviewed By: cipolleschi
Differential Revision: D44630645
fbshipit-source-id: 472c3967449dfb99f845a82d9e9c49efc343021c
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/36902
Reverts https://github.com/facebook/react-native/pull/36584.
Since we've come across example packages (typically targeting Node.js) which only distribute ESM, we believe it's more helpful to return to asserting the `"import"` condition by default, for maximum compatibility. The above issue and comments outline the pros/cons.
Changelog:
[General][Changed] - Default condition set for experimental Package Exports is now ['require', 'import', 'react-native']
Metro changelog: [Experimental] Package Exports unstable_conditionNames now defaults to ['require', 'import']
Reviewed By: robhogan
Differential Revision: D44962143
fbshipit-source-id: 004172388916c902469b49cfc920ebe13c62c430
Summary:
Changelog: [Internal]
Publishing to check CI if bumping and aligning in the same commit will work, since these new versions are not available on npm yet, but maybe our new monorepo setup will resolve this
**Adding back `react-native/virtualized-lists` as a workspace to `xplat/js` so that it won't be resolved from npm**
#publish-packages-to-npm
Pull Request resolved: https://github.com/facebook/react-native/pull/36556
Reviewed By: cipolleschi
Differential Revision: D44255353
Pulled By: hoxyq
fbshipit-source-id: 21372487d6e9c0b2382b7cd9af835beed46b8ce1
Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/36623
Changelog:
[General][Changed] - The default `metro.config.js` in apps now extends `react-native/metro-config`, and should be updated in existing apps.
~~`react-native/rn-get-polyfills.js` is removed and should be updated to `react-native/js-polyfills` in existing apps (this is part of the new default config).~~
#publish-packages-to-npm
## Context
### React Native Metro config → React Native repo (https://github.com/facebook/react-native/pull/36502)
We (the React Native team) are aiming to relocate the default Metro config for React Native out of `react-native-community/cli-plugin-metro` and **into the React Native repo + app template** as a new `react-native/metro-config` package.
This is the first (and minimum viable) phase we can ship to separate the release process of Metro from RN CLI in order to reduce coupling and iterate faster for our users.
**See full motivation, design, and test plan (which previewed the CLI bump) here: https://github.com/facebook/react-native/pull/36502**
## Changes
NOTE: This PR is pending the inclusion of a bump to `react-native-community/cli`, and will be sequenced after https://github.com/react-native-community/cli/pull/1875 is merged.
- Upgrade `react-native-community/cli` to `11.0.0`, upgrade all `metro` packages to `0.76.0` (version distributed in this CLI release).
- Update the `metro.config.js` file in `packages/react-native/template/`.
- Now merges defaults from `react-native/metro-config`, and can be used with CLI >= 11.0.0.
- Update the `metro.config.js` files for `packages/react-native/` and `packages/rn-tester/` (these are integration test locations).
- Now merges defaults from `react-native/metro-config`, and can be used with CLI >= 11.0.0.
Changes to `react-native/metro-config` — `0.72.1` (prepared but not depended on yet):
- Export `mergeConfig` util (removing direct `metro-config` dependency in consuming projects).
- Explicitly depend on `metro-react-native-babel-transformer` and `metro-runtime` (transitively included today).
Reviewed By: cortinico, blakef
Differential Revision: D44099691
fbshipit-source-id: 405635dd69fd50a1e9548279eaeda3c932b5b167
Summary:
X-link: https://github.com/facebook/metro/pull/955
Pull Request resolved: https://github.com/facebook/react-native/pull/36584
Changelog:
[General][Changed] - Default condition set for experimental Package Exports is now `['require', 'react-native']`
The [Exports RFC](https://github.com/react-native-community/discussions-and-proposals/blob/main/proposals/0534-metro-package-exports-support.md) had assumed that supporting the `"import"` condition was a syntax-only difference, given we are not in a Node.js environment — and so was worthwhile to support for maximal ecosystem compatibility.
{F915841105}
This assumption is similar to [`--moduleResolution bundler` in TypeScript 5.0](https://github.com/microsoft/TypeScript/pull/51669):
> bundlers and runtimes that include a range of Node-like resolution features and ESM syntax, but do not enforce the strict resolution rules that accompany ES modules in Node or in the browser
> -- https://github.com/microsoft/TypeScript/pull/51669#issue-1467004047
However, robhogan has rightly pointed out that **we should not do this!**
- ESM (once transpiled) is **not** simply a stricter subset of in-scope features supported by CJS. For example, it supports top-level async, which would be breaking at runtime.
- We recently made the same change for our Jest environment:
- https://github.com/facebook/react-native/commit/681d7f8113d2b5e9d6966255ee6c72b50a7d488a
As such, we are erring on the side of correctness and supporting only `['require', 'react-native']` in our defaults. At runtime, all code run by React Native is anticipated to be CommonJS. `"exports"` will instead allow React Native to correctly select the CommonJS versions of modules from all npm packages.
Metro changelog: [Experimental] Package Exports `unstable_conditionNames` now defaults to `['require']`
Reviewed By: robhogan
Differential Revision: D44303559
fbshipit-source-id: 0077e547e7775e53d1e4e9c3a9d01347f4fb7d4a
Summary:
Changelog:
[General][Added] - Add `react-native/metro-config` package
Pull Request resolved: https://github.com/facebook/react-native/pull/36502
## Context
### React Native Metro config → React Native repo (https://github.com/facebook/react-native/pull/36502)
We (the React Native team) are aiming to relocate the default Metro config for React Native out of `react-native-community/cli-plugin-metro` and **into the React Native repo + app template** as a new `react-native/metro-config` package.
This is the first (and minimum viable) phase we can ship to separate the release process of Metro from RN CLI in order to reduce coupling and iterate faster for our users.
**See full motivation, design, and test plan here: https://github.com/facebook/react-native/pull/36502**
## Changes
- This PR adds the new `react-native/metro-config` package, reproduces all static values previously defined in RN CLI. The values which remain in RN CLI are dynamic values derived from CLI options passed by the user.
{F906910591}
Reviewed By: cortinico
Differential Revision: D44099692
fbshipit-source-id: 672a67e19d866ac2c64fc84983b5d82c604918c6
