## Summary
- Updated `webpack` (and all related packages) to v5 in
`react-devtools-*` packages.
- I haven't touched any `TODO (Webpack 5)`. Tried to poke it, but each
my attempt failed and parsing hook names feature stopped working. I will
work on this in a separate PR.
- This work is one of prerequisites for updating Firefox extension to
manifests v3
related PRs:
https://github.com/facebook/react/pull/22267https://github.com/facebook/react/pull/26506
## How did you test this change?
Tested on all surfaces, explicitly checked that parsing hook names
feature still works.
The old version of prettier we were using didn't support the Flow syntax
to access properties in a type using `SomeType['prop']`. This updates
`prettier` and `rollup-plugin-prettier` to the latest versions.
I added the prettier config `arrowParens: "avoid"` to reduce the diff
size as the default has changed in Prettier 2.0. The largest amount of
changes comes from function expressions now having a space. This doesn't
have an option to preserve the old behavior, so we have to update this.
* Facebook -> Meta in copyright
rg --files | xargs sed -i 's#Copyright (c) Facebook, Inc. and its affiliates.#Copyright (c) Meta Platforms, Inc. and affiliates.#g'
* Manual tweaks
The existential type `*` was deprecated and a codemod provided to replace it. Ran that and did some manual fixups:
```sh
node_modules/.bin/flow codemod replace-existentials --write .
```
ghstack-source-id: 4c98b8db6a
Pull Request resolved: https://github.com/facebook/react/pull/25416
This commit builds on PR #22260 and makes the following changes:
* Adds a DevTools feature flag for named hooks support. (This allows us to disable it entirely for a build via feature flag.)
* Adds a new Suspense cache for dynamically imported modules. (This allows a component to suspend while importing an external code chunk– like the hook names parsing code).
* DevTools supports a hookNamesModuleLoaderFunction param to import the hook names module. I wish this could be handles as part of the react-devtools-shared package, but I'm not sure how to configure Webpack (4) to serve the chunk from react-devtools-inline. This seemed like a reasonable workaround.
The PR also contains an additional unrelated change:
* Removes pre-fetch optimization (added in DevTools: Improve named hooks network caching #22198). This optimization was mostly only important for cases where sources needed to be re-downloaded, something which we can now avoid in most cases¹ thanks to using cached responses already loaded by the page. (I tested this locally on Facebook and this change has no negative performance impact. There is still some overhead from serializing the JS through the Bridge but that's constant between the two approaches.)
¹ The case where we don't benefit from cached responses is when DevTools are opened after the page has already loaded certain scripts. This seems uncommon enough that I don't think it justified the added complexity of prefetching.
