В доке по useLayoutEffect можно найти следующие отрывки:
- React guarantees that the code inside useLayoutEffect and any state updates scheduled inside it will be processed before the browser repaints the screen.
- Call useLayoutEffect perform the layout measurements before the browser repaints the screen:
- The code inside useLayoutEffect and all state updates scheduled from it block the browser from repainting the screen. When used excessively, this makes your app slow. When possible, prefer useEffect.
Как это возможно? Как Реакт может гарантировать что код внутри useLayoutEffect и стейт апдейты запланированные внутри него будут выполнены до перерисовки экрана браузером? Как Реакт может влиять на перерисовку браузером, как может ее блокировать? Как Реакт это делает и как вы
A userstyle that makes you wait ten seconds before entering a Hacker News thread. I use stylus to manage mine.
.subtext {
display: inline-block;
background: linear-gradient(to left, transparent 50%, #f60 50%) right;
Unless otherwise noted (either in this file or in a file's copyright section) the contents of this gist are Copyright ©️2020 by Christopher Allen, and are shared under spdx:Creative Commons Attribution Share Alike 4.0 International (CC-BY-SA-4.) open-source license.
If you more tips and advice like these, you can become a monthly patron on my GitHub Sponsor Page for as little as $5 a month; and your contributions will be multipled, as GitHub is matching the first $5,000! This gist is all about Homebrew, so if you like it you can support it by donating to them or becoming one of their Github Sponsors.
I've recently ran into a pitfall of [React.memo()][memo] that seems generally overlooked; skimming over the top results in Google just finds it mentioned in passing in a [React issue][regit], but not in the [FAQ] or API [overview][react-api], and not in the articles that set out to explain React.memo() (at least the ones I looked at). The issue is specifically that nesting children defeats memoization, unless the children are just plain text. To give a simplified code example:
const Memoized = React.memo(({ children }) => (<div>{children}</div>));
// Won't ever re-render
<Memoized>bar</Memoized>
// Will re-render every time; the memoization does nothing
If you're using a high-end bluetooth headset on your Macbook Pro it's likely your mac is using an audio codec which favors battery efficiency over high quality. This results in a drastic degradation of sound, the SBC codec is the likely culprit, read more about it here.
- Play a song on your headphones
- Option (⌥) click the Bluetooth button at the top of your screen
- If you're using AAC or aptX, you can stop here—those are the highest quality codecs.
If you use server rendering, keep in mind that neither useLayoutEffect nor useEffect can run until the JavaScript is downloaded.
You might see a warning if you try to useLayoutEffect on the server. Here's two common ways to fix it.
If this effect isn't important for first render (i.e. if the UI still looks valid before it runs), then useEffect instead.
function MyComponent() {
| /** | |
| * OnLayout is built upon: View (and ResizeObserver), StyleSheet | |
| */ | |
| const elementBreakpoints = { | |
| small: { minWidth: 200 }, | |
| medium: { minWidth: 300 } | |
| large: { minWidth: 500 } | |
| }; | |