We have a reactJs application which works fine on all other browsers except safari on macOS and ios. The app works perfectly on Chrome on macOs or windows and ios as well.
Also, once the app freezes, we cannot open dev console in safari and if it is open, most of the things don't work like pausing script execution. And we can say from activity monitor that it goes in some infinite loop as the cpu usage of that page goes to 100% but i am unable to figure out as there are no errors at all and it works on other browsers.
It just freezes on loading and becomes totally unresponsive (No scroll or clicks etc). It looks like there is some infinite loop or dependency issue.
The webapp is kind of LMS and has many dependencies but to give you an idea here is the stack -
GraphQL
React Router Dom
React Hooks
Sentry for Logging
Socket
etc
If you have any questions feel free to ask.
Here is the site - https://i3.stage.cudy.co/
Thanks
I went into trying to see what's going on and I noticed three things:
First couple of times I tried to open your site it froze as you say. Could not even open dev tools.
After previous tries, I suddenly saw the icons for your menu options (browse tutors, assignments, feeds, etc) appear and everything worked "fine" and no more freezes.
However, I did noticed a bunch of errors in dev tools. Most of them are related to urls not allowed to access and some others due a /profiles trying to access an API of some sort.
You have a lot of unhandled promise rejections errors in your *.js so that may also be something to look at.
I would suggest tackling down the cross domain origin policies first and then add logic to handle the promise rejections that you're missing since sometimes those unhandled scenarios leave the app at the dark without knowing what to do and may interrupt your logic process thus rendering frozen sites because of that.
Last but not less important, this is a good way of tracing down the issue.
There are way too many factors involved for us to help you without looking at the code.
I'd recommend the following:
Going through the code history and testing it on each major version change so you can rule out any culprits or suspicions.
I'd disconnect any packages 1 by 1.
Disconnect the API so see if it's a server issue where you're requesting API calls infinitely or something silly like that.
If disconnecting the API works then you know where to look at.
Cheers
Related
When developing my react app the app becomes unusably slow with the devtools open in chrome. Works fast and fine with them closed or in incognito mode. I have tried disabling all extensions and had the same problem. This seems to have started happening recently when I updated chrome (now on Version 80.0.3987.132).
I am not really sure where to start debugging this issue but it has become very frustrating to develop on my app.
Any advice or help debugging would be appreciated.
TL;DR: Go to the Sources tab and delete all breakpoints for the site.
I had a similar problem. My site was very slow to load, but only in specific circumstances:
Dev-tools were open.
Tab was in a normal window. (not incognito mode)
Profiling was not enabled.
If (and only if) all three of those conditions were met, the site would load unbearably slowly (15+ seconds; normally ~3s), plus have performance issues for certain operations on the site (like changing which subpanel was open). It was very strange.
Like you, I tried disabling all of my extensions, yet the problem persisted.
Attempt 1: I tried clearing all of the site's cookies and local-storage, using the info/lock dropdown at the left of the address-bar. Suprisingly, that seems to have fixed it! (edit: this was not the root problem; see below for that)
So the problem must be that my site was storing too much data in local storage or something, such that dev-tools was choking on it (but only in specific cases, for some reason). This also matches with the issue resolving in incognito mode: incognito mode uses a "clear slate" for site cookies/local-storage.
Anyway, it's an odd one, but the cookies/local-storage clearing seems to have worked for my case. (If the issue comes up again, and the solution above doesn't fix it, I'll try to remember to mention it.)
Update: Oddly, having the profiler on still speeds things up even after the fix (ie. those three conditions being met still slows down page loading and actions, just much less than before the fix). So apparently the fix merely "reduces the intensity" of the problem rather than fully fixing it; like, by resetting local-storage, it lessens the size of that data, which somehow is a variable affecting the core problem (not yet identified).
Attempt 2: I believe I have found the root problem and solution: I removed all breakpoints for the site, and the slowdown was solved completely. So the problem seems to be that I had lots of unneeded breakpoints set at various places in my website code (some enabled, some disabled). Some of these must have been placed in/near "hotspots" that were getting called frequently. By having the dev-tools open, the Javascript engine must have had to start performing some processing related to the breakpoints, slowing things down.
My guess is that the problem would also be fixed by disabling the "JavaScript source maps" settings (as that's the only thing I can think would cause so much slowdown), but I haven't confirmed this.
This has most probably something to do with this commit, titled "Stop sending profile data when recording is off".
They already know there is an issue with the Developer Tools slowing down and they tried to prevent it by preventing profiling data to be sent via the bridge to the frontend, when not recording.
As reported, it seems the issue is not happening anymore, on the latest version. However, the cause is still unknown.
Try uninstalling the Developer Tools extension, clearing browser cache and then installing it again.
You should probably try using a version other than the one you're using, Version 80.0.3987.132. The app you are trying to develop might not be suitable to the version you are using. Delete the extension you are using, clear and remove every trace of browser cache and then re-download the extension, like what Daniele Molinari said. It might help. If it doesn't let me know. I'll try a different approach.
I hope it's the right place to ask such question. I have a live react app which still runs in development mode since it requires frequent updates, and it seems that for a few users the website doesn't function properly while for the others it works perfectly.
For example, for a few users there is a button that just doesn't respond, although I created some code to log to the console that the button was pressed, and it does also for those users, but then the rest of the code just doesn't run.
For other users, there is some text that loaded from mongodb database, and for those users it reverses some of the words in a random fashion.
I'm really lost here and don't even know where to begin, since for me and most of the users everything is working fine.
Do you think it could be because the app still runs in development mode?
Recently I noticed that a few users received the message
the development server has disconnected. refresh the page if necessary.
I researched this and was suggested that I should upgrade my react-scripts. I did, and the problem vanished, but the other problems still persist.
I understand that it's like shooting in the dark and it's hard to give advices without knowing more information, but maybe you could point me in the right direction?
Thank you very much in advance
I have an native mobile application that loads my react application within a child iframe (not sure exactly how it does it), but this application injects some variables into the page as windows.xxxx
So in order to test my application (yes, this sucks a lot) I need to run the app on my phone, have it open up the URL on my development machine (aka http://192.168.10.10:3300).
Then to debug anything I'm forced to alert(var1) .. as you can imagine this is a pretty painful process and I really wish the parent application would provide something better than this.
Normally a simple option would be something like console.log(var1) but I can't see the console on my mobile device and my URL is being loaded withing this native app.
So:
1. Any suggestions on a better debug process would be welcome.
2. One idea that would help is if there was a react component that would simply
print to screen anything any console.log().
3. I guess another option could be some kind of remote logger, so that console.remotelog(debugServerUrl, var1) pushes debug messages to the listener which then displays the debug.
All of this if a pain of course, but hoping someone out there has a clever idea for me.
If you're already using ReactJS, an easy quick-fix might be creating a log file in the phone. This post details a quick and relatively easy way to save a string as a text file, and it would not be hard to put everything you want saved into a string.
Furthermore, This post details an implementation of the remote logging feature you vaguely referenced.
Also, if you want to capture stdout and stderr, check out this npm package
Ultimately, hope this helps, and good luck
This is a weird one I've only recently noticed since Chrome 60.0.3112.90 on Mac OS X 10.11.6, and it really impacts my daily work.
Chrome is creating a new console context every time an Angular application is reloaded, and the previous instances (presumably) stick around. This makes working in the console difficult because the context of the console sometimes remains on an old context. Whats worse is you cannot even interact with an old context so why does it remain?
I'm unsure if this is a UI bug or an actual issue with the Angular application possibly keeping reference to something from the previous context (not sure how or what would even do that).
This occurs on both the product I work on, and on the Angular documentation website.
Here's a gif of it happening:
http://i.imgur.com/lVjLJnu.gifv
Every time you see me click outside of the console, I'm performing a reload.
Any ideas? This is absolutely obnoxious. I've disabled all extensions with no difference. My colleagues on Linux do not have this problem.
I'm trying to capture a website using PhantomJS, in particupar I'm using Pageres.
This website has got:
AngularJS
LocalStorage use
AJAX requests to an API
So, I'm testing locally and I'm not getting expected results, sometimes the screenshot will work with errors -rendering part of the contents, sometimes it won't render complete contents.
It really looks like Pagerer gets not enough time to take the screenshot once the site has fully loaded. I already added delay option but it will fail anyways, actually I could said it has worked better with out the delay option.
This is what it should be rendered:
And when it has worked best, this is what I get:
This is my code for rendering:
var pageres = new Pageres({})
.src('fantastica.a2015.mediotiempo.com', ['1440x900'], {delay: 3, crop: false});
pageres.on('warn', function (err,obj) {console.log(err,obj)});
pageres.run(function (err, screenshot) {
screenshot[0].pipe(response);
});
And, (I know there would be MUCH code to explain now) this is JS code being rendered.
Any particular advice?
Be aware of the differences between Phantom versions.
Phantom 1.9.x (which Pageres is using) is a browser engine from quite a few years ago (Chrome 13 is the closest equivalent) and will not render many HTML5 features.
Phantom 2.x is a much more modern webkit engine. But because of: a) because they have not produced a ready-made linux binary; b) some small API changes, projects like CasperJS and Pageres are holding back on supporting it. According a comment in https://github.com/sindresorhus/pageres/issues/77 if you make your own binary, and symlink to it, it works.
Also be aware that SlimerJS is an alternative to PhantomJS, based on Firefox rather than WebKit. There is no similar project based on Blink (to get screenshots how a modern Chrome would render them), but there is TrifleJS for IE. (However the Pageres pages say it is not the goal of the project to support other engines.)
Wait for DOM elements to appear, rather than using a delay.
Ajax calls, delayed loading, etc. make things very hard to predict. So, enter a polling loop, and don't take your screenshot until the DOM element you want in your screenshot is now visible. CasperJS has waitForSelector() for this case. PhantomJS has the slightly lower-level waitFor().
I think pageres would need a bit of hacking to add this functionality.