Closed shirakaba closed 4 years ago
There's some confusion. The new DevTools doesn't enable hot reloading (or have anything to do with reloading). Rather, the hot reloading changes Dan has been working on makes use of the "hook" that DevTools and React use to communicate. It adds itself into the middle so it can do reloading.
I've edited the title to remove mention of DevTools (since it may cause confusion).
As for the question about how the new HMR should be used, I don't think I know the latest thinking there. I see @gaearon has a wip PR over on the CRA repo: https://github.com/facebook/create-react-app/pull/5958
As for the question about how the new HMR should be used, I don't think I know the latest thinking there. I see @gaearon has a wip PR over on the CRA repo:
To clarify for readers, that PR is very outdated and not relevant anymore.
I need to write something down about how Fast Refresh works and how to integrate it. Haven't had time yet.
Okay, here goes.
It's a reimplementation of "hot reloading" with full support from React. It's originally shipping for React Native but most of the implementation is platform-independent. The plan is to use it across the board — as a replacement for purely userland solutions (like react-hot-loader
).
Theoretically, yes, that's the plan. Practically, someone needs to integrate it with bundlers common on the web (e.g. Webpack, Parcel). I haven't gotten around to doing that yet. Maybe someone wants to pick it up. This comment is a rough guide for how you’d do it.
Fast Refresh relies on several pieces working together:
module.hot
API lets you do this.react-reconciler@0.21.0
or higher for custom renderersreact-refresh/runtime
entry pointreact-refresh/babel
Babel pluginYou'll probably want to work on the integration part. I.e. integrating react-refresh/runtime
with Webpack "hot module replacement" mechanism.
⚠️⚠️⚠️ TO BE CLEAR, THIS IS A GUIDE FOR PEOPLE WHO WANT TO IMPLEMENT THE INTEGRATION THEMSELVES. THIS IS NOT A GUIDE FOR BEGINNERS OR PEOPLE WHO WANT TO START USING FAST REFRESH IN THEIR APPS. PROCEED AT YOUR OWN CAUTION! ⚠️⚠️⚠️
There are a few things you want to do minimally:
react-refresh/babel
to your Babel pluginsAt that point your app should crash. It should contain calls to $RefreshReg$
and $RefreshSig$
functions which are undefined.
Then you need to create a new JS entry point which must run before any code in your app, including react-dom
(!) This is important; if it runs after react-dom
, nothing will work. That entry point should do something like this:
if (process.env.NODE_ENV !== 'production' && typeof window !== 'undefined') {
const runtime = require('react-refresh/runtime');
runtime.injectIntoGlobalHook(window);
window.$RefreshReg$ = () => {};
window.$RefreshSig$ = () => type => type;
}
This should fix the crashes. But it still won't do anything because these $RefreshReg$
and $RefreshSig$
implementations are noops. Hooking them up is the meat of the integration work you need to do.
How you do that depends on your bundler. I suppose with webpack you could write a loader that adds some code before and after every module executes. Or maybe there's some hook to inject something into the module template. Regardless, what you want to achieve is that every module looks like this:
// BEFORE EVERY MODULE EXECUTES
var prevRefreshReg = window.$RefreshReg$;
var prevRefreshSig = window.$RefreshSig$;
var RefreshRuntime = require('react-refresh/runtime');
window.$RefreshReg$ = (type, id) => {
// Note module.id is webpack-specific, this may vary in other bundlers
const fullId = module.id + ' ' + id;
RefreshRuntime.register(type, fullId);
}
window.$RefreshSig$ = RefreshRuntime.createSignatureFunctionForTransform;
try {
// !!!
// ...ACTUAL MODULE SOURCE CODE...
// !!!
} finally {
window.$RefreshReg$ = prevRefreshReg;
window.$RefreshSig$ = prevRefreshSig;
}
The idea here is that our Babel plugin emits calls to this functions, and then our integration above ties those calls to the module ID. So that the runtime receives strings like "path/to/Button.js Button"
when a component is being registered. (Or, in webpack's case, IDs would be numbers.) Don't forget that both Babel transform and this wrapping must only occur in development mode.
As alternative to wrapping the module code, maybe there's some way to add a try/finally like this around the place where the bundler actually initializes the module factory. Like we do here in Metro (RN bundler). This would probably be better because we wouldn't need to bloat up every module, or worry about introducing illegal syntax, e.g. when wrapping import
with in try / finally
.
Once you hook this up, you have one last problem. Your bundler doesn't know that you're handling the updates, so it probably reloads the page anyway. You need to tell it not to. This is again bundler-specific, but the approach I suggest is to check whether all of the exports are React components, and in that case, "accept" the update. In webpack it could look like something:
// ...ALL MODULE CODE...
const myExports = module.exports;
// Note: I think with ES6 exports you might also have to look at .__proto__, at least in webpack
if (isReactRefreshBoundary(myExports)) {
module.hot.accept(); // Depends on your bundler
enqueueUpdate();
}
What is isReactRefreshBoundary
? It's a thing that enumerates over exports shallowly and determines whether it only exports React components. That's how you decide whether to accept an update or not. I didn't copy paste it here but this implementation could be a good start. (In that code, Refresh
refers to react-refresh/runtime
export).
You'll also want to manually register all exports because Babel transform will only call $RefreshReg$
for functions. If you don't do this, updates to classes won't be detected.
Finally, the enqueueUpdate()
function would be something shared between modules that debounces and performs the actual React update.
const runtime = require('react-refresh/runtime');
let enqueueUpdate = debounce(runtime.performReactRefresh, 30);
By this point you should have something working.
There are some baseline experience expectations that I care about that go into "Fast Refresh" branding. It should be able to gracefully recover from a syntax error, a module initialization error, or a rendering error. I won't go into these mechanisms in detail, but I feel very strongly that you shouldn't call your experiment "Fast Refresh" until it handle those cases well.
Unfortunately, I don't know if webpack can support all of those, but we can ask for help if you get to a somewhat working state but then get stuck. For example, I've noticed that webpack's accept()
API makes error recovery more difficult (you need to accept a previous version of the module after an error), but there's a way to hack around that. Another thing we'll need to get back to is to automatically "register" all exports, and not just the ones found by the Babel plugin. For now, let's ignore this, but if you have something that works for e.g. webpack, I can look at polishing it.
Similarly, we'd need to integrate it with an "error box" experience, similar to react-error-overlay
we have in Create React App. That has some nuance, like the error box should disappear when you fix an error. That also takes some further work we can do once the foundation's in place.
Let me know if you have any questions!
Syntax errors / initialization errors should be "easy enough" to handle in some way before telling React to start a render, but how would rendering errors interact with error boundaries?
If a rendering error happens, it'll trigger the closest error boundary which will snapshot itself into an error state, and there is no generic way to tell error boundaries that their children are magically possibly fixed after a live refresh. Does / should every refreshable component get its own error boundary for free, or does error handling work differently in the reconciler when the runtime support is detected on initialization?
all of the exports are React components, and in that case, "accept" the update
Is there any way to detect such components? As far as I understand - no. Except export.toString().indexOf('React')>0
, but it would stop working with any HOC applied.
Plus self accepting at the end of the file is not error-prone - the new accept handle would not be established, and next update would bubble to the higher boundary, that's why require("react-hot-loader/root").hot
was created.
In any case - it seems to be that if one would throw all react-specific code from react-hot-loader
, keeping the external API untouched - that would be enough, and applicable to all existing installations.
Using react-refresh/babel
0.4.0 is giving me this error on a large number of files:
ERROR in ../orbit-app/src/hooks/useStores.ts
Module build failed (from ../node_modules/babel-loader/lib/index.js):
TypeError: Cannot read property '0' of undefined
at Function.get (/Users/nw/projects/motion/orbit/node_modules/@babel/traverse/lib/path/index.js:115:33)
at NodePath.unshiftContainer (/Users/nw/projects/motion/orbit/node_modules/@babel/traverse/lib/path/modification.js:191:31)
at PluginPass.exit (/Users/nw/projects/motion/orbit/node_modules/react-refresh/cjs/react-refresh-babel.development.js:546:28)
I narrowed down that file to the simplest thing that causes it:
import { useContext } from 'react'
export default () => useContext()
If a rendering error happens, it'll trigger the closest error boundary which will snapshot itself into an error state, and there is no generic way to tell error boundaries that their children are magically possibly fixed after a live refresh.
Fast Refresh code inside React remembers which boundaries are currently failed. Whenever a Fast Refresh update is scheduled, it will always remount them.
If there are no boundaries, but a root failed on update, Fast Refresh will retry rendering that root with its last element.
If the root failed on mount, runtime.hasUnrecoverableErrors()
will tell you that. Then you have to force a reload. We could handle that case later, I didn’t have time to fix it yet.
Using react-refresh/babel 0.4.0 is giving me this error on a large number of files:
File a new issue pls?
Is there any way to detect such components?
I linked to my implementation, which itself uses Runtime.isLikelyAReactComponent()
. It’s not perfect but it’s good enough.
the new accept handle would not be established, and next update would bubble to the higher boundary
Can you make an example? I’m not following. Regardless, that’s something specific to the bundler. I made Metro do what I wanted. We can ask webpack to add something if we’re missing an API.
The goal here is to re-execute as few modules as possible while guaranteeing consistency. We don’t want to bubble updates to the root for most edits.
it seems to be that if one would throw all react-specific code from react-hot-loader, keeping the external API untouched
Maybe, although I’d like to remove the top level container as well. I also want a tighter integration with the error box. Maybe that can still be called react-hot-loader
.
By the way I edited my guide to include a missing piece I forgot — the performReactRefresh
call. That’s the thing that actually schedules updates.
isLikelyComponentType(type) {
return typeof type === 'function' && /^[A-Z]/.test(type.name);
},
I would not feel safe with such logic. Even if all CapitalizedFunctions are React components almost always - many modules (of mine) has other exports as well. For example exports-for-tests. That's not a problem, but creates some unpredictability - hot boundary could be created at any point... or not created after one line change.
What could break isLikelyComponentType
test:
mapStateToProps
(for tests, not used in a production code)hook
(and that's ok)Class
which might be not a react class (would not, but should)So - there would be cases when hot boundary shall be established, but would not, and there would be a cases when hot boundary would be established, but shall not. Sounds like old good unstable hot-reloading we both don't quite like :)
There is one place where applying hot boundary would be not so unpredictable, and would be quite expected - a thing
or domain
boundary, or a directory index, ie an index.js
reexporting a "public API" from the Component.js
in the same directory (not a Facebook style afaik).
In other words - everything like you did in Metro, but with more limitations applied. Everything else, like linting rule to have such boundary established for any lazy loaded component, could be used to enforce the correct behaviour.
Speaking of which - hot fast refresh would handle Lazy? Is it expected to have boundary from the other side of the import
?
Gave it a quick try to see the magic in the browser and it is so nice :) I did the simplest possible thing, i.e. hardcoding all the instrumentation code, so no webpack plugins there yet
Repo here: https://github.com/pekala/react-refresh-test
Just curious but for webpack, couldn't you just have a babel plugin to wrap the try/finally? Just want to be sure I'm not missing something before giving it a shot.
The Babel plugin is not environment specific. I’d like to keep it that way. It doesn’t know anything about modules or update propagation mechanism. Those differ depending on the bundler.
For example in Metro there’s no try/finally wrapping transform at all. Instead I put try/finally in the bundler runtime itself around where it calls the module factory. That would be ideal with webpack too but I don’t know if it lets you hook into the runtime like that.
You could of course create another Babel plugin for wrapping. But that doesn’t buy you anything over doing that via webpack. Since it’s webpack-specific anyway. And it can be confusing that you could accidentally run that Babel plugin in another environment (not webpack) where it wouldn’t make sense.
You can, by hooking into the compilation.mainTemplate.hooks.require
waterfall hook. The previous invocation of it is the default body of the __webpack_require__
function, so you can tap into the hook to wrap the contents into a try/finally
block.
The problem is getting a reference to React inside the __webpack_require__
. It's possible, but might require some degree of reentrancy and recursion guards.
For more details, check MainTemplate.js
and web/JsonpMainTemplatePlugin.js
in the webpack source code. JsonpMainTemplatePlugin
itself just taps into a bunch of hooks from MainTemplate.js
so that's probably the "meat" that you need to tackle.
Here's a harebrained prototype I hacked together that does effectively what Dan outlined above. It's woefully incomplete, but proves out a lo-fi implementation in webpack: https://gist.github.com/maisano/441a4bc6b2954205803d68deac04a716
Some notes:
react-dom
is hardcoded here, so this would not work with custom renderers or sub-packages (e.g. react-dom/profiling
).umd
library target.The problem is getting a reference to React inside the __webpack_require__. It's possible, but might require some degree of reentrancy and recursion guards.
I assume you mean getting a reference to Refresh Runtime.
In Metro I’ve solved this by doing require.Refresh = RefreshRuntime
as early as possible. Then inside the require
implementation I can read a property off the require
function itself. It won’t be available immediately but it won’t matter if we set it early enough.
@maisano I had to change a number of things, and ultimately I'm not seeing the .accept function called by webpack. I've tried both .accept(module.i, () => {})
and .accept(() => {})
(self-accepting, except this doesn't work in webpack). The hot
property is enabled, I see it come down and run through accepted modules.
So I ended up patching webpack to call self-accepting modules, and that was the final fix.
Here's the patch:
diff --git a/node_modules/webpack/lib/HotModuleReplacement.runtime.js b/node_modules/webpack/lib/HotModuleReplacement.runtime.js
index 5756623..7e0c681 100644
--- a/node_modules/webpack/lib/HotModuleReplacement.runtime.js
+++ b/node_modules/webpack/lib/HotModuleReplacement.runtime.js
@@ -301,7 +301,10 @@ module.exports = function() {
var moduleId = queueItem.id;
var chain = queueItem.chain;
module = installedModules[moduleId];
- if (!module || module.hot._selfAccepted) continue;
+ if (!module || module.hot._selfAccepted) {
+ module && module.hot._selfAccepted()
+ continue;
+ }
if (module.hot._selfDeclined) {
return {
type: "self-declined",
I know this goes against their API, which wants that to be an "errorCallback", I remember running into this specifically many years ago working on our internal HMR, and ultimately we ended up writing our own bundler. I believe parcel supports the "self-accepting" callback API. Perhaps it's worth us opening an issue on webpack and seeing if we can get it merged? @sokra
So ... I further polished the plugin based on the work of @maisano : https://github.com/pmmmwh/react-refresh-webpack-plugin (I wrote it in TypeScript because I don't trust myself fiddling with webpack internals when I started, I can convert that to plain JS/Flow)
I tried to remove the need of a loader for injecting the hot-module code with webpack Dependency
classes, but seemingly that will require a re-parse of all modules (because even with all functions inline, we still need a reference to react-refresh/runtime
in somewhere).
Another issue is that there are no simple ways (afaik) to detect JavaScript-like files in webpack - for example html-webpack-plugin
uses the javascript/auto
type as well, so I hard-coded what seems to be an acceptable file mask (JS/TS/Flow) for loader injection.
I also added error recovery (at least syntax error) based on comment from @gaearon in this 5-year old thread. Next is recovering from react errors - I suspect this can be done by injecting a global error boundary (kinda like AppWrapper
of react-hot-loader
), which will also tackle the error-box interface, but did not have the time to get to that just quite yet.
The issue raised by @natew is also avoided - achieved by decoupling the enqueueUpdate
call and the hot.accpet(errorHandler)
call.
@pmmmwh What timing! I just created a repo which built on/tweaked a little of the work I had shared in the gist.
I haven't gotten to error-handling in any case, though the plugin here is a bit more solid than the initial approach I had taken.
Next is recovering from react errors - I suspect this can be done by injecting a global error boundary (kinda like AppWrapper of react-hot-loader), which will also tackle the error-box interface, but did not have the time to get to that just quite yet.
That should already work out of the box. No need for a custom error boundary or wrapping here.
Next is recovering from react errors - I suspect this can be done by injecting a global error boundary (kinda like AppWrapper of react-hot-loader), which will also tackle the error-box interface, but did not have the time to get to that just quite yet.
That should already work out of the box. No need for a custom error boundary or wrapping here.
@gaearon Strange. I tried throwing errors in rendering function components - if the error occurs in return
, HMR works, but if it occurs somewhere else, it sometimes won't work.
@pmmmwh What timing! I just created a repo which built on/tweaked a little of the work I had shared in the gist.
I haven't gotten to error-handling in any case, though the plugin here is a bit more solid than the initial approach I had taken.
@maisano What should I say? I actually started working on this and got stuck with the dependency injection issue last weekend ... Your gist provided me the way out :tada:
if the error occurs in return, HMR works, but if it occurs somewhere else, it sometimes won't work.
I would need more details about what you tried exactly and what you mean by “works” and “doesn’t work”.
There are many things that can go wrong if the module bundler integration isn’t implemented correctly (which is the topic or this thread). I would expect that there’s nothing in React itself that prevent recovery from errors introduced during edits. You can verify that it works in React Native 0.61 RC3.
@pmmmwh, @maisano the following check skips modules with components as named exports and no refresh boundary is established:
const desc = Object.getOwnPropertyDescriptor(moduleExports, key);
if (desc && desc.get) {
// Don't invoke getters as they may have side effects.
return false;
}
I don't know why this is needed in Metro
, but in webpack
getters just return the named exports and as far as I can tell there are no side effects. So it should be safe to remove.
@gaearon React.lazy
components (e.g. code-split routes) are not being re-rendered. Is that by design? I can see that the refresh boundary is established but performReactRefresh()
does not seem to do anything. Changes to lazy children refresh fine, so this isn't a big deal, but I'm wondering if we're doing something wrong...
lazy
is a little state machine - it hold reference to the old component, and that reference has to be updated.
Now let's imagine it was, and now is referring to a brand new lazy
object) - it will have to go thought loading
phase again, and that would probably destroy all nested tree.
I would expect lazy to work. Maybe something broke. I need to see a reproducing case.
Since there’s been a few prototypes, should we pick one and then move this discussion to its issues? And iterate there.
There is:
https://github.com/maisano/react-refresh-plugin
and:
https://github.com/pmmmwh/react-refresh-webpack-plugin
I've set up a fork of pmmmwh's plugin that works with webpack@5.0.0-alpha
(also fixes named exports):
https://github.com/WebHotelier/webpack-fast-refresh
What about react-hot-loader
?
react-hot-loader
backported almost all features from fast refresh
, but there are few historical and integrational moments, which are not letting backport all, and, honestly, there is no sense to reimplement them in "rhl" terms. So - let it retire.
another one: https://github.com/yiminghe/react-refresh-loader
I would need more details about what you tried exactly and what you mean by “works” and “doesn’t work”.
There are many things that can go wrong if the module bundler integration isn’t implemented correctly (which is the topic or this thread). I would expect that there’s nothing in React itself that prevent recovery from errors introduced during edits. You can verify that it works in React Native 0.61 RC3.
After a few tweaks, I can verify that it works.
However - it seems that the babel plugin wasn't working for classes. I have checked and this seems to happen regard-less of the implementation, as all injected code and react-refresh/runtime
works properly. I am not sure if this is intended or if it is webpack specific, if it is the latter I can try to land a fix tomorrow. (I also tested this with only the metro preset, reproduce gist here)
I am kinda sure that it works for RN, but on my current machine I don't have an environment handy to test on RN so if you can point me to the implementation of babel plugin in metro or the transforms that would be really helpful.
Since there’s been a few prototypes, should we pick one and then move this discussion to its issues? And iterate there.
Maybe we can go here? Since my last comment I have ported the whole project into plain JS and added some fixes on update queuing. I haven't got to porting the plugin for webpack@5, but after reading the fork by @apostolos and the new HMR logic in webpack@next, the fixes should be straight-forward.
Yes, Babel plugin won’t register classes. The intention is that this would happen at the module system level. Each export should be checked for being “likely” a React component. (A checking function is provided by the runtime.) If true, register the export, just like the Babel plugin would. Give it an ID like filename exports%export_name
. This is what makes classes work in Metro, as Babel plugin won’t find them.
In other words, since we can’t preserve class state anyway, we might as well entrust “locating” them to the module exports boundary instead of trying to find them inline in the source code with a transform. Exports should act as a “catch all” for components we didn’t find with the plugin.
Mailchimp started using a fork of the plugin I shared last. It's been fleshed out a tiny bit more and folks who've opted into using it seem to be quite happy. We're going to continue to iterate on it locally. I plan to remove the fork and publish updates upstream once it's a bit further along.
@gaearon Thoughts on adding a Symbol we can attach to things that we know are safe for refresh, but aren't components? For example we have a pattern like:
export default create({
id: '100'
})
export const View = () => <div />
Where create
just returns an object. I've patched it for now on my end, but we could easily add a symbol to the default export object there that indicates this is a safe file. Not sure the best pattern exactly.
Edit: I did realize this can go into the refresh implementation! I thought it may be better in the runtime but perhaps not. With so many different impls of the loader it may be nicer to have a standard way.
Let's forward 10 years. What your codebase looks like? Allow here, disallow there? How to keep these flags up to date? How to reason about? Like there are safe to update locations, and unsafe, you have to preserve, or can't properly reconcile by some reason. Which reasons in each case are valid reasons?
symbols
you will have more - about force allow
reload, or force disallow
reloadHi folks 👋 I'm looking to lend a hand here. Have we agreed on a single repo/effort?
Is it this repo shared by @pmmmwh? https://github.com/pmmmwh/react-refresh-webpack-plugin
Or is it this repo shared by @maisano? https://github.com/maisano/react-refresh-plugin
Looks like the one by @pmmmwh has been committed to more recently. Unless I hear otherwise I'm going to assume that's the one to focus on.
Implementation in Parcel 2 has started here: https://github.com/parcel-bundler/parcel/pull/3654
Yay!
For anyone looking for it, an implementation of React Refresh for Rollup projects using Nollup for development: https://github.com/PepsRyuu/rollup-plugin-react-refresh
Probably not the cleanest implementation, but it works.
For webpack solutions, it looks like there hasn't been any official release of the above plugins, so it seems the best HMR solution for react is Dan's library here still: https://github.com/gaearon/react-hot-loader
We just shipped Parcel 2 alpha 3 with support for Fast Refresh out of the box! Feel free to try it out. 😍 https://twitter.com/devongovett/status/1197187388985860096?s=20
🥳 added deprecation note to RHL 🥳
A recipe I've been using to to try this out on CRA apps using @pmmmwh's work in progress, react-app-rewired
, and customize-cra
:
npx create-react-app <project_dir> --typescript
npm install -D react-app-rewired customize-cra react-refresh babel-loader https://github.com/pmmmwh/react-refresh-webpack-plugin
Edit ./package.json
:
"scripts": {
"start": "react-app-rewired start",
"build": "react-app-rewired build",
"test": "react-app-rewired test",
"eject": "react-app-rewired eject"
},
Add ./config-overrides.js
file:
// eslint-disable-next-line
const { addBabelPlugin, addWebpackPlugin, override } = require('customize-cra');
// eslint-disable-next-line
const ReactRefreshPlugin = require('react-refresh-webpack-plugin');
/* config-overrides.js */
module.exports = override(
process.env.NODE_ENV === 'development'
? addBabelPlugin('react-refresh/babel')
: undefined,
process.env.NODE_ENV === 'development'
? addWebpackPlugin(new ReactRefreshPlugin())
: undefined,
);
Enjoying the experience so far. Thanks for all the work from everyone involved!
Thanks @drather19 !
~~I created a repository based on your instruction, it works: https://github.com/jihchi/react-app-rewired-react-refresh If someone would like to give it a try and save some typing, feel free to clone the repo.~~
Please refer to https://github.com/pmmmwh/react-refresh-webpack-plugin/tree/master/examples/cra-kitchen-sink
AND ... v0.1.0
for Webpack is just shipped 🎉
@drather19 @jihchi You guys might want to switch over to that version - it includes a more unified experience as well as a lot of bug fixes on the initial implementation.
@pmmmwh supports ts-loader
+ babel-loader
?
@pmmmwh supports
ts-loader
+babel-loader
?
I did test against TS with Babel only and it works, so if it doesn't work when you use ts+babel loaders please feel free to file an issue :)
@drather19 I tried cloning and running your repo but the dev server never starts up.
Environment, OS - OSX 10.14.6 Node - v12.13.0 Yarn -1.19.2
@pmmmwh - FYI
react-app-rewired-react-refresh on master is 📦 v0.1.0 via ⬢ v12.13.0
❯ yarn start
yarn run v1.19.2
$ react-app-rewired start | cat
ℹ 「wds」: Project is running at http://192.168.1.178/
ℹ 「wds」: webpack output is served from /
ℹ 「wds」: Content not from webpack is served from /Users/seanmatheson/Development/temp/react-app-rewired-react-refresh/public
ℹ 「wds」: 404s will fallback to /index.html
Starting the development server...
Dan Abramov mentioned that Devtools v4 will be making
react-hot-loader
obsolete: https://twitter.com/dan_abramov/status/1144715740983046144?s=20I can't see any mention of HMR in the Devtools documentation, however; now that
react-hot-loader
has become obsolete (and with it, therequire("react-hot-loader/root").hot
method), how should we set up apps for HMR in:I'd be particularly interested in a migration guide specifically for anyone who's already set up HMR via
react-hot-loader
.Also, for HMR, does it matter whether we're using the standalone Devtools or the browser-extension Devtools?