Thread of my favorite web performance tools 🚀
1) slowfil.es by @csswizardry and @RyanTownsend gives you a URL with a huge (and customizable) server response time.

Super convenient to test what happens when a CSS or JS files takes forever to load. Image
2) input-delay.glitch.me by @notwaldorf shows how it feels to have a laggy input field. (It’s the most irritating tool ever.)

bl.ocks.org/esjewett/2b188… by @esjewett does the same – but for mouse cursor.

Both tools are 💯 for demos. Image
(Semi-related: a 3-minute Microsoft video that shows how *huge* a difference between a 100 ms latency and a 5 ms latency feels.)
3) statoscope.tech by @smelukov is a modern version of webpack.github.io/analyse/. A bit less detailed, but so much nicer!

My primary use case: drop a webpack stats file → see why exactly that specific huge file is bundled. Image
4) web-vitals-report.web.app builds a Core Web Vitals report based on your Google Analytics data (but you need to send CWV data into GA explicitly).

Haven’t had a chance to use it yet (don’t collect CWV data with GA), but should be a great helpful tool for some clients. Image
5) Also, datastudiohelp.com/core-web-vital… explains how to get a Core Web Vitals report in Google Data Studio. (It’s actually quick! Just clone a template and change the url.)

Unlike with the previous tool, you don’t need to collect any data yourself! The report uses CrUX data. Image
6) usehooks.com/useWhyDidYouUp… is a React hook that prints why a specific component rerendered. Just copy and paste it! Perfect for debugging runtime performance of a single component 💅

Like github.com/welldone-softw…, but much less invasive. Image
7) meowni.ca/font-style-mat… (yet another tool by @notwaldorf!) lets you find a fallback font that matches your custom font as closely as possible.

If you ever had a high CLS score because the layout jumped after a custom font loaded, this is for you. Image
(Oh, and shameless plug: in addition to these tools above, I also have a GitHub list with 50+ webpack performance tools and plugins: github.com/iamakulov/awes…) Image
8) glyphhanger, which makes fonts smaller by removing any characters your page doesn’t need (and more). And it’s a one-line command!

Image

• • •

Missing some Tweet in this thread? You can try to force a refresh
 

Keep Current with Ivan Akulov

Ivan Akulov Profile picture

Stay in touch and get notified when new unrolls are available from this author!

Read all threads

This Thread may be Removed Anytime!

PDF

Twitter may remove this content at anytime! Save it as PDF for later use!

Try unrolling a thread yourself!

how to unroll video
  1. Follow @ThreadReaderApp to mention us!

  2. From a Twitter thread mention us with a keyword "unroll"
@threadreaderapp unroll

Practice here first or read more on our help page!

More from @iamakulov

Jun 15
Gah I’m really excited about <Suspense> and hydration in React 18.

With React 16-17, `.hydrate()` is often the most expensive JS call in the whole app. You start hydrating the app – and the page freezes for, like, a second: Image
In React 18, `.hydrate()` is still expensive by default.

But! If you wrap parts of the app (or the whole app) with <Suspense>, React will take these parts – and instead of hydrating them in one go, will hydrate them in chunks, 5-10 ms at a time: Image
Under the hood, React uses performance​.now() and isInputPending() APIs to check how long rendering takes. If rendering takes more than 5-50 ms, or if isInputPending() returns `true`, React pauses rendering and yields to the browser.

Here’s how the check is implemented: Image
Read 5 tweets
May 5
Oh look, my favorite app Spotify being slow!

Also it’s 1 am meaning it’s the best time to do some performance profiling.

Thread ⬇️
Spotify is an Electron app, meaning we can use Chrome DevTools to profile it. To enable Chrome DevTools in Spotify, I install `spicetify` and run `spicetify enable-devtools`.

Yay!
Now, let’s go to Chrome DevTools → Performance → Record, switch between playlists a couple times, and stop the recording. This is what we’ll get ↓

What can we see here?
Read 16 tweets
Jun 24, 2020
Okay, let’s do a thing!

One like of this tweet = one web perf tip. Loading perf, runtime perf, whatever ⬇
1) If you do a perf recording of a React app (in the dev mode), the perf trace will include the Timings section.

In Timings, you can see what components were rendered, and when. Useful to debug unnecessary renders: Image
(Unfortunately, React is removing that due to complexity: github.com/facebook/react…. But it’s still available in the most part of React 16.x)
Read 68 tweets

Did Thread Reader help you today?

Support us! We are indie developers!


This site is made by just two indie developers on a laptop doing marketing, support and development! Read more about the story.

Become a Premium Member ($3/month or $30/year) and get exclusive features!

Become Premium

Don't want to be a Premium member but still want to support us?

Make a small donation by buying us coffee ($5) or help with server cost ($10)

Donate via Paypal

Or Donate anonymously using crypto!

Ethereum

0xfe58350B80634f60Fa6Dc149a72b4DFbc17D341E copy

Bitcoin

3ATGMxNzCUFzxpMCHL5sWSt4DVtS8UqXpi copy

Thank you for your support!

Follow Us on Twitter!

:(