Is there a way to automatically test performance (maybe in terms of FPS) of React applications regularly in CI pipelines? Any tools for this out there?
Is this something you have actually experienced? Can you cite an example of running into this issue? I've built fairly complex UIs with React (tables with nested dropdowns, financial statements with a lot of data points, dynamic charts / graphs, elements with animations, etc. and haven't run into this issue.
The only time I've seen people have trouble w/ performance is when they use something like Redux or Apollo on top of React. The problem in those cases of course is Redux or Apollo, not React itself.
I blame it on create-react-app, which feels very very bloated to me. Whenever I write React from scratch it feels super performant, even with Redux and much more complex layouts than the page I mentioned.
as a Create React App maintainer I'd love if you could share some scenarios where CRA itself would cause performance issues. CRA itself is mostly just developer tooling and every other feature is opt-in. The team and many contributors (including people on WebPack team) have spent quite a lot of time on optimizing the production builds CRA produces; building an React only app won't have much else than React and React-DOM itself, while we also automatically do more advanced things like bundle spitting too.
It’s also useful to instrument this in your production environment (called real user metrics) for some % of user sessions and combine it with more synthetic tests.
The backend is of course really easy, just measure request times (min/avg/max) and time to first byte.
Edit: Don’t know why I’m being downvoted for this answer? Lol
https://medium.com/@paularmstrong/twitter-lite-and-high-perf...
https://github.com/markerikson/react-redux-links/blob/master...
Might be worth going through. Hopefully they're useful.
While it's probably not 100% relevant, you might also want to glance at some of the things I've done trying to benchmark performance for the React-Redux library itself, including running benchmarks in Puppeteer and capturing metrics like render times and FPS [0].
Now, my experience has been that I have to deliberately crank up the number of components on screen and dispatch absurd numbers of Redux actions a second just to get the FPS to drop below 60FPS, so I'm not sure how much that would be applicable to real-world apps, but at least you can see how I've tried to capture the values.
As a general observation, I'd highly encourage folks to use the Profiler that's built into the React DevTools to view render behavior and find components that may be re-rendering when it wasn't necessary [1] [2].
Also, Brian Vaughn has been working on a major rewrite of the React DevTools to both improve internal speed and add new features, and you can play around with it now [3].
Finally, if you _really_ want to get fine-grained, there's a little-known profiling/tracing API that can be used to capture render times in parts of your app [4] [5] [6].
[0] https://github.com/reduxjs/react-redux-benchmarks
[1] https://reactjs.org/blog/2018/09/10/introducing-the-react-pr...
[2] https://www.netlify.com/blog/2018/08/29/using-the-react-devt...
[3] https://github.com/bvaughn/react-devtools-experimental
[4] https://github.com/bvaughn/rfcs/blob/profiler/text/0000-prof...
[5] https://gist.github.com/bvaughn/8de925562903afd2e7a12554adcd...
[6] https://gist.github.com/bvaughn/25e6233aeb1b4f0cdb8d8366e54a...
- https://firebase.google.com/docs/perf-mon/get-started-web (this is a new feature released by Google. Luckily you don't need Firebase to use this. https://www.youtube.com/watch?v=KYYjdWSrRjI&t is a good tutorial on wiring your app up)
- https://reactjs.org/docs/perf.html
- lighthouse by Google
You could just run lighthouse on your app periodically for an in depth audit on your site. That way you wouldn't need to slow down your builds with a test (not sure what's best practice here. Just trying to throw out some basic ideas)
If I were to set this up I'd use devtools to throttle the network down to 3g, and I would actually render the browser in the test.
https://github.com/webdriverio/webdriverio/tree/master/packa...
- lighthouse (https://github.com/GoogleChrome/lighthouse). You can implement this with their Node CLI to automate in your pipeline and output the results somewhere.
- calibre (https://calibreapp.com/). Gives you nice graphs and snapshots over time.
