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feat[devtools/extension]: show disclaimer when page doesnt run react and refactor react polling logic (facebook#27373)
Changes: 1. Refactored react polling logic, now each `.eval()` call is wrapped in Promise, so we can chain them properly. 2. When user has browser DevTools opened and React DevTools panels were mounted, user might navigate to the page, which doesn't have React running. Previously, we would show just blank white page, now we will show disclaimer. Disclaimer appears after 5 failed attempts to find React. We will also show this disclaimer if it takes too long to load the page, but once any React instance is loaded and registered, we will update the panels. 3. Dark theme support for this disclaimer and popups in Firefox & Chromium-based browsers **Important**: this is only valid for case when React DevTools panels were already created, like when user started debugging React app and then switched to non-React page. If user starts to debug non-React app (by opening browser DevTools for it), we will not create these panels, just like before. Q: "Why do we poll to get information about react?" A: To handle case when react is loaded after the page has been loaded, some sandboxes for example. | Before | After | | --- | --- | | <img width="1840" alt="Screenshot 2023-09-14 at 15 37 37" src="https://github.com/facebook/react/assets/28902667/2e6ffb39-5698-461d-bfd6-be2defb41aad"> | <img width="1840" alt="Screenshot 2023-09-14 at 15 26 16" src="https://github.com/facebook/react/assets/28902667/1c8ad2b7-0955-41c5-b8cc-d0fdb03e13ca"> |
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‎packages/react-devtools-extensions/panel.html

Lines changed: 34 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -22,11 +22,44 @@
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right: 0;
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bottom: 0;
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}
25+
.no-react-disclaimer {
26+
margin: 16px;
27+
font-family: Courier, monospace, serif;
28+
font-size: 16px;
29+
animation: fadeIn .5s ease-in-out forwards;
30+
}
31+
32+
@keyframes fadeIn {
33+
0% {
34+
opacity: 0;
35+
}
36+
100% {
37+
opacity: 1;
38+
}
39+
}
40+
41+
@media (prefers-color-scheme: dark) {
42+
:root {
43+
color-scheme: dark;
44+
}
45+
46+
@supports (-moz-appearance:none) {
47+
:root {
48+
background: black;
49+
}
50+
51+
body {
52+
color: white;
53+
}
54+
}
55+
}
2556
</style>
2657
</head>
2758
<body>
2859
<!-- main react mount point -->
29-
<div id="container">Unable to find React on the page.</div>
60+
<div id="container">
61+
<h1 class="no-react-disclaimer">Looks like this page doesn't have React, or it hasn't been loaded yet.</h1>
62+
</div>
3063
<script src="./build/panel.js"></script>
3164
</body>
3265
</html>

‎packages/react-devtools-extensions/popups/shared.css

Lines changed: 11 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -7,7 +7,17 @@ body {
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}
88

99
@media (prefers-color-scheme: dark) {
10-
html {
10+
:root {
1111
color-scheme: dark;
1212
}
13+
14+
@supports (-moz-appearance:none) {
15+
:root {
16+
background: black;
17+
}
18+
19+
body {
20+
color: white;
21+
}
22+
}
1323
}

‎packages/react-devtools-extensions/src/background/index.js

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -64,8 +64,8 @@ chrome.runtime.onConnect.addListener(port => {
6464
const tabId = port.sender.tab.id;
6565

6666
if (ports[tabId]?.proxy) {
67-
port.disconnect();
68-
return;
67+
ports[tabId].disconnectPipe?.();
68+
ports[tabId].proxy.disconnect();
6969
}
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7171
registerTab(tabId);

‎packages/react-devtools-extensions/src/main/index.js

Lines changed: 34 additions & 65 deletions
Original file line numberDiff line numberDiff line change
@@ -22,6 +22,7 @@ import {
2222
setBrowserSelectionFromReact,
2323
setReactSelectionFromBrowser,
2424
} from './elementSelection';
25+
import {startReactPolling} from './reactPolling';
2526
import cloneStyleTags from './cloneStyleTags';
2627
import injectBackendManager from './injectBackendManager';
2728
import syncSavedPreferences from './syncSavedPreferences';
@@ -30,60 +31,6 @@ import getProfilingFlags from './getProfilingFlags';
3031
import debounce from './debounce';
3132
import './requestAnimationFramePolyfill';
3233

33-
// Try polling for at least 5 seconds, in case if it takes too long to load react
34-
const REACT_POLLING_TICK_COOLDOWN = 250;
35-
const REACT_POLLING_ATTEMPTS_THRESHOLD = 20;
36-
37-
let reactPollingTimeoutId = null;
38-
export function clearReactPollingTimeout() {
39-
clearTimeout(reactPollingTimeoutId);
40-
reactPollingTimeoutId = null;
41-
}
42-
43-
export function executeIfReactHasLoaded(callback, attempt = 1) {
44-
clearReactPollingTimeout();
45-
46-
if (attempt > REACT_POLLING_ATTEMPTS_THRESHOLD) {
47-
return;
48-
}
49-
50-
chrome.devtools.inspectedWindow.eval(
51-
'window.__REACT_DEVTOOLS_GLOBAL_HOOK__ && window.__REACT_DEVTOOLS_GLOBAL_HOOK__.renderers.size > 0',
52-
(pageHasReact, exceptionInfo) => {
53-
if (exceptionInfo) {
54-
const {code, description, isError, isException, value} = exceptionInfo;
55-
56-
if (isException) {
57-
console.error(
58-
`Received error while checking if react has loaded: ${value}`,
59-
);
60-
return;
61-
}
62-
63-
if (isError) {
64-
console.error(
65-
`Received error with code ${code} while checking if react has loaded: ${description}`,
66-
);
67-
return;
68-
}
69-
}
70-
71-
if (pageHasReact) {
72-
callback();
73-
} else {
74-
reactPollingTimeoutId = setTimeout(
75-
executeIfReactHasLoaded,
76-
REACT_POLLING_TICK_COOLDOWN,
77-
callback,
78-
attempt + 1,
79-
);
80-
}
81-
},
82-
);
83-
}
84-
85-
let lastSubscribedBridgeListener = null;
86-
8734
function createBridge() {
8835
bridge = new Bridge({
8936
listen(fn) {
@@ -370,6 +317,7 @@ function ensureInitialHTMLIsCleared(container) {
370317
function createComponentsPanel() {
371318
if (componentsPortalContainer) {
372319
// Panel is created and user opened it at least once
320+
ensureInitialHTMLIsCleared(componentsPortalContainer);
373321
render('components');
374322

375323
return;
@@ -389,7 +337,7 @@ function createComponentsPanel() {
389337

390338
createdPanel.onShown.addListener(portal => {
391339
componentsPortalContainer = portal.container;
392-
if (componentsPortalContainer != null) {
340+
if (componentsPortalContainer != null && render) {
393341
ensureInitialHTMLIsCleared(componentsPortalContainer);
394342

395343
render('components');
@@ -408,6 +356,7 @@ function createComponentsPanel() {
408356
function createProfilerPanel() {
409357
if (profilerPortalContainer) {
410358
// Panel is created and user opened it at least once
359+
ensureInitialHTMLIsCleared(profilerPortalContainer);
411360
render('profiler');
412361

413362
return;
@@ -427,7 +376,7 @@ function createProfilerPanel() {
427376

428377
createdPanel.onShown.addListener(portal => {
429378
profilerPortalContainer = portal.container;
430-
if (profilerPortalContainer != null) {
379+
if (profilerPortalContainer != null && render) {
431380
ensureInitialHTMLIsCleared(profilerPortalContainer);
432381

433382
render('profiler');
@@ -442,7 +391,7 @@ function createProfilerPanel() {
442391

443392
function performInTabNavigationCleanup() {
444393
// Potentially, if react hasn't loaded yet and user performs in-tab navigation
445-
clearReactPollingTimeout();
394+
clearReactPollingInstance();
446395

447396
if (store !== null) {
448397
// Store profiling data, so it can be used later
@@ -479,7 +428,7 @@ function performInTabNavigationCleanup() {
479428

480429
function performFullCleanup() {
481430
// Potentially, if react hasn't loaded yet and user closed the browser DevTools
482-
clearReactPollingTimeout();
431+
clearReactPollingInstance();
483432

484433
if ((componentsPortalContainer || profilerPortalContainer) && root) {
485434
// This should also emit bridge.shutdown, but only if this root was mounted
@@ -531,6 +480,8 @@ function connectExtensionPort() {
531480
}
532481

533482
function mountReactDevTools() {
483+
reactPollingInstance = null;
484+
534485
registerEventsLogger();
535486

536487
createBridgeAndStore();
@@ -541,18 +492,36 @@ function mountReactDevTools() {
541492
createProfilerPanel();
542493
}
543494

544-
// TODO: display some disclaimer if user performs in-tab navigation to non-react application
545-
// when React DevTools panels are already opened, currently we will display just blank white block
546-
function mountReactDevToolsWhenReactHasLoaded() {
547-
function onReactReady() {
548-
clearReactPollingTimeout();
549-
mountReactDevTools();
495+
let reactPollingInstance = null;
496+
function clearReactPollingInstance() {
497+
reactPollingInstance?.abort();
498+
reactPollingInstance = null;
499+
}
500+
501+
function showNoReactDisclaimer() {
502+
if (componentsPortalContainer) {
503+
componentsPortalContainer.innerHTML =
504+
'<h1 class="no-react-disclaimer">Looks like this page doesn\'t have React, or it hasn\'t been loaded yet.</h1>';
505+
delete componentsPortalContainer._hasInitialHTMLBeenCleared;
506+
}
507+
508+
if (profilerPortalContainer) {
509+
profilerPortalContainer.innerHTML =
510+
'<h1 class="no-react-disclaimer">Looks like this page doesn\'t have React, or it hasn\'t been loaded yet.</h1>';
511+
delete profilerPortalContainer._hasInitialHTMLBeenCleared;
550512
}
513+
}
551514

552-
executeIfReactHasLoaded(onReactReady, 1);
515+
function mountReactDevToolsWhenReactHasLoaded() {
516+
reactPollingInstance = startReactPolling(
517+
mountReactDevTools,
518+
5, // ~5 seconds
519+
showNoReactDisclaimer,
520+
);
553521
}
554522

555523
let bridge = null;
524+
let lastSubscribedBridgeListener = null;
556525
let store = null;
557526

558527
let profilingData = null;

‎packages/react-devtools-extensions/src/main/reactPolling.js

Lines changed: 103 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,103 @@
1+
/* global chrome */
2+
3+
class CouldNotFindReactOnThePageError extends Error {
4+
constructor() {
5+
super("Could not find React, or it hasn't been loaded yet");
6+
7+
// Maintains proper stack trace for where our error was thrown (only available on V8)
8+
if (Error.captureStackTrace) {
9+
Error.captureStackTrace(this, CouldNotFindReactOnThePageError);
10+
}
11+
12+
this.name = 'CouldNotFindReactOnThePageError';
13+
}
14+
}
15+
16+
export function startReactPolling(
17+
onReactFound,
18+
attemptsThreshold,
19+
onCouldNotFindReactAfterReachingAttemptsThreshold,
20+
) {
21+
let status = 'idle';
22+
23+
function abort() {
24+
status = 'aborted';
25+
}
26+
27+
// This function will call onSuccess only if React was found and polling is not aborted, onError will be called for every other case
28+
function checkIfReactPresentInInspectedWindow(onSuccess, onError) {
29+
chrome.devtools.inspectedWindow.eval(
30+
'window.__REACT_DEVTOOLS_GLOBAL_HOOK__ && window.__REACT_DEVTOOLS_GLOBAL_HOOK__.renderers.size > 0',
31+
(pageHasReact, exceptionInfo) => {
32+
if (status === 'aborted') {
33+
onError(
34+
'Polling was aborted, user probably navigated to the other page',
35+
);
36+
return;
37+
}
38+
39+
if (exceptionInfo) {
40+
const {code, description, isError, isException, value} =
41+
exceptionInfo;
42+
43+
if (isException) {
44+
onError(
45+
`Received error while checking if react has loaded: ${value}`,
46+
);
47+
return;
48+
}
49+
50+
if (isError) {
51+
onError(
52+
`Received error with code ${code} while checking if react has loaded: "${description}"`,
53+
);
54+
return;
55+
}
56+
}
57+
58+
if (pageHasReact) {
59+
onSuccess();
60+
return;
61+
}
62+
63+
onError(new CouldNotFindReactOnThePageError());
64+
},
65+
);
66+
}
67+
68+
// Just a Promise wrapper around `checkIfReactPresentInInspectedWindow`
69+
// returns a Promise, which will resolve only if React has been found on the page
70+
function poll(attempt) {
71+
return new Promise((resolve, reject) => {
72+
checkIfReactPresentInInspectedWindow(resolve, reject);
73+
}).catch(error => {
74+
if (error instanceof CouldNotFindReactOnThePageError) {
75+
if (attempt === attemptsThreshold) {
76+
onCouldNotFindReactAfterReachingAttemptsThreshold();
77+
}
78+
79+
// Start next attempt in 0.5s
80+
return new Promise(r => setTimeout(r, 500)).then(() =>
81+
poll(attempt + 1),
82+
);
83+
}
84+
85+
// Propagating every other Error
86+
throw error;
87+
});
88+
}
89+
90+
poll(1)
91+
.then(onReactFound)
92+
.catch(error => {
93+
// Log propagated errors only if polling was not aborted
94+
// Some errors are expected when user performs in-tab navigation and `.eval()` is still being executed
95+
if (status === 'aborted') {
96+
return;
97+
}
98+
99+
console.error(error);
100+
});
101+
102+
return {abort};
103+
}

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