Preventing React re-renders with composition
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- Опубликовано: 11 янв 2023
- 👉 Advanced React Book: www.advanced-react.com
👉 Comprehensive guide on React re-renders (www.developerway.com/posts/re...)
👉 How to useMemo and useCallback: you can remove most of them (www.developerway.com/posts/ho...)
👉 The mystery of React Element, children, parents and re-renders (www.developerway.com/posts/re...)
💬 Twitter: / adevnadia
💬 Linkedin: / adevnadia
Looking into how re-renders of React components can be prevented with the help of three composition patterns.
#react #reactjs #webdevelopment #programming #frontend
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Nadia you're an underrated content creator! You break down concepts clearly both on your blog and here. Am going to dive deeper into all your other articles.
Thank you, so nice to hear 😊
I never write comments, but this one deserves huge credit for great explanation
omg, your videos about react are so didactic that they took away my anxiety of not being able to deal with performance problems, thank you!!
thank you, that's so nice to hear! 😊
Enjoying these new patterns of writing. A lot better than other RUclipsrs out there suggesting to just 'deal' with the re-renders... Thanks so much for these! 🤙🏾🤙🏾🙏🏽🙏🏽
Great perf patterns! I will now think about "Isolate state changes" when adding state to a component! It helps to use more composition and test components more easily.
Here after reading your blog.
last week I discovered your blogs and now the vids. Amazing stuffs. I'm building a crypto exchange UI with React and your blogs are helping me a lot. Thank you very much. Keep sharing knowledge.
this content is gold! thanks for such a great detailed explanation on how to properly handle states!
This is probably the best video about why and how composition reduce re-renders. great stuff!
wow, you are awesome. One of the best content creators, God gifted explanation skills.
Great explanation!. You earned a subscriber. I hope your channel experiences steady growth
this series are making me realize I've been writing some terrible things lol, nice work keep it up!! 🙌
Thanks for the video, I encountered the first problem with modal (your first example) in a real world project with Material UI modals. The modal component accepts a prop "open" to show it, at first I saw that with a naive approach (useState + modal inside the parent) I'll trigger a re-render on the parent, so first solution, I opted to useRef + forwardRef and I extracted modals as reusable components, then I used a Redux store to save a key+open and dispatch an open/close modal action from the parent with the modal id as key, the modal will have its own id as key and a call to useSelector to see if it's open or not. In fact, extracting as shown in your video was not a solution to make the parent component easy to read.
This content is pure gold
talk about boiling things down and getting to the point. thank you for this. amazing.
I just discovered this channel and the content quality is so good. Love your videos :)
Cheers! Really helpful to have these fundamental patterns explained in one place and so concisely.
Love your way of teaching. Very clear and organized. And sweet animations!
I'm really enjoying your React tutorials! Your explanations are clear and concise, and I'm learning a lot.
Valuable gems, thanks for putting this video and your articles together. Learned some valuable info.
WOw, best way to explain with editing, Keep going on.
Very well explained and concise thank you !!
this is a great video - useful, practical, and well-explained
Absolutely loved the presentation and example. We know these but using this on the fly and for keeping these concepts in mind , such examples really help. Thanks
Great video, just keep going. Your material are great source of knowledge both YT and Your website.
oh wow, this video is pretty new.
explained beautifully and clearly as well. made me re-think everything I have done so far. thank you so much!
Love your content! Very clear presentation and absolutely amazing! Thank you for your sharing!
Watching these videos after reading those long blog posts cements many of the ideas Nadia always talks about. Thank you so much for sharing🙏
Thank you very much Nadia. Very insightful!!
Simple and very clear explanation 👌
Very educative. Keep them coming in
This is just what I needed, thank you so much!!
Simple and informative performance patterns.
very clear and concise
Great video, very helpful. Thanks for sharing!
Nadia, your content is incredible and I'm glad I found you! I already bought your book and have been enjoying it a lot. Love the way you teach, please keep it up
Thank you! 😊
you are so amazing, this video helped me so much
Very very helpful! Thanks!
This was very useful. Thank you!
Packed full of valuable content ❤
Great video! Thanks!
Thanks so much!!! for your great explanation!
you are really underated creator
Thank you VERY much Nadia Makarevich, I was missing some fundamentals on this and your article (and maybe this video is as useful) helped a LOT. It was so clear. Maybe I should have read the official docs from the very beginning I started using React hahaha
Your content is a treasure, I have read again and again and again your blog, and I have learned a crazy amount of stubs. Thanks a lot!!!
Thank you, glad the blog was useful! 😊
This was quite enlightening as it was refreshing. I think I've leveled up my React Skills in this video. I just subscribed.
Awesome to hear! 😊
Great content! Thanks
great video. It really helped! Thank you
Good job! Thanks to the author a lot!
this is brilliant!
Wow amazing explanation, I'm going to use this good practice from now on, just to mention all the content I have found out there just tells you to use Memoization but you track the main problem and offer the best solution, Thanks for it and Greetings from Mexico
Glad you liked it! 😊
Great! Very useful info.
Please provide more videos in any topic on react 🙂Your content is awesome and practical
great content! thanks
Thanks! This is awesome!
Wow, you're amazing!
Awesome 🎉 this is super crazy and valuable at the same!!
This is very amazing. Thank you so much, big W !!!
brilliant!
wonder full tutorial mam, i loved your explanation 💌
Golden content
Amazing stuff..
Great job
keep up your work
great content please make more videos
very nice, thank you
Thanks ❤❤❤
omg
Thx a lot!
Thanks for creating such a great video .. From your article, I came here.. Could you please include a separate tab for react hooks in your article .. This would be very helpful to me and other developers.
I love the content, this is uniqe, this is what I am looking for, when I search about performance in react.
I would to see more of your videos about how useMemo and useCallback helps us.
one small request, can you please make a video on how bad formik is, in performance when you are working with big forms. if you want more details on this, then i am happy to provide my struggles on it. Thanks You man.
great video :)
Awesome video
thanks Nadia
This is gold 🪙🪙🪙🥇
Thanks, Also we can work in such an MVVM architecture and manage the states on the presenter/controller and consume it in variant components.
Interesting content
awesome video, thanks for the advice to avoid caveats
wtf great content!!! keep it up
видео просто супер
Спасибо 💌
Thank you so much for explaining these concepts, one question though: passing many components as props at multiple levels wouldn't make it look terrible at the top level? Like some pyramid of code that mabey makes you scroll-x in your code editor to fully see?
It might! 🙂 No silver bullet for anything. Those are just techniques that are useful for certain cases, but over-use of them might result in unreadable code that doesn't make sense
Great
Great work and thx! One questio if I may?
Example with scroll tracking?
Is that compontent usefull? How would we fire a callback or some logic without re-render?
Updating the state in the wrapper is not usefull for itself, ins't it?
That really depends on what you want to do with that logic, hard to answer without seeing a real-life usecase or code. There are multiple options here, like throttling or exposing that state through render props (if some external component needs access to it without being re-rendered)
Loved this video! I didn't know props didn't affect changes on the state, thanks so much for going through all possible scenarios we can use in order to avoid unnecessary re-render!
Can you also explain on the case where I can useSelector for example:
const { trainingMode } = useSelector((state) => state);
const { checkedIn } = useSelector((state) => state.checkin);
Is there any implications on using only state or state.somethingElse when it comes to re-render?
`useSelector` I assume is something like `reselect` library? Of normal state or React Context it won't matter, re-renders will be triggered at the fact that the state/Context value changes.
If you're using Redux or other library, I would need to double check how it behaves, depends on the library
How would you go about preventing rerenders in list generated with Array.map? If the list is passed as a children prop, you end up in a scenario where a prop depends on another prop, ie, , and you can't pass props to props.children in the render code. Nice videos. Thanks
❤
Is there any optimization difference between Component as a children and Component as a prop pattern ? I found both of them to be quite similar in terms of efficiency, as in both the cases the children or the props don't get re-rendered on state updates ? Lovely video BTW 💛
No difference that I know of, children are props, just have nicer jsx "nesting" syntax :)
@@developerwaypatterns That's what I thought too :)
Great video!
How would you go about the ButtonWithDialog example if the component had a datagrid in it, and when clicking an item we want to open up the by passing an id.
Then it feels like we need to have [id, setId] inside of the component which forces it to rerender?
const Component = () => {
const [id, setId] = useState(0)
const [open, setOpen] = useState(false)
const handleItemClick = (id: number) => (
setId(id)
setOpen(true)
}
return (
{open &&
}
Yeah, in this case Datagrid will re-render. If it's something you need to prevent, you'd have to either go with React.memo for it, or pass that id through Context/any state management solutions you use
I've jump to codebase that written the code like that at 10:50, and the code is mess and re-rendering like crazy... there is not good way to stop re-rendering in react, unless to slowly started switching to solidjs.
ragarding the last example with column and content. What would you say if Layout still wraps children, and and inside the Layout they are accessed via array destructuring, const [column, content] = children, and then used at appropriate places? I don't see any benefits over 'components as chidren', just wandering if that could be an alternative
For me, that would be confusing - I would understand what the intention is I'd say, but it would take a few seconds from my mental capacity to figure it out. So I'd rather go with some more "traditional" approach.
From performance/re-renders perspective it doesn't look like it would bring any benefit either 🤔
Thank you, I have a question, how can find our components are re-rendered or not? Create a useEffect on them without second entry? What is your way to test and debug when you have no request to an API
This will work. Also, just console.log in render function will be good for it most of the time.
And a lot of people like this tool for this: github.com/welldone-software/why-did-you-render
@@developerwaypatterns 🌹♥
How do you track which components re-render? I'm a newbie and what I would think to do is add a console.log to every file, to see if it's re-rendered (which, I'm sure, is not the best way to do it).
You can also use tools like "why-did-you-render": github.com/welldone-software/why-did-you-render
@@developerwaypatterns хороший инструмент, сам им пользуюсь.
I dont get it, you say that if state changes within a component it will make it re-render completely, but then at 7:00 you say that if state changes children are not affected because they are just props, but they should be re-rendered as a whole because of the state change, no?
Nope, that's the beauty of passing components as children! If you think of the components as a tree, then when state change triggers a re-render, it will be propagated "down" the tree, not up. And if you pass components as props, they will be "above" in that tree, so they will not be affected.
@@developerwaypatterns Thanks for this answer!
I was struggling with this as well and just cant get why it is works like that.
By the way I bought your books and it is amazing! Thanks a lot for such great and structured content and for the videos as well!
@@Antoshkiv1 Thank you! 😊
One suggestion please try to use dark themes in your video
at around 6:50 I found it really hard to understand.
so components in the RETURN statement is not the same as {children} ? so there is a differentiation?
"children are just props" just isn't really a comfortable reason to justify them not re-rendering. they are still components?
I tried reading your blog posts too but I'm still struggling to understand your explanations.
this is the explanation:
“children” is a element that is created in SomeOutsideComponent. When MovingComponent re-renders because of its state change, its props stay the same. Therefore any Element (i.e. definition object) that comes from props won’t be re-created, and therefore re-renders of those components won’t happen.
how does the props "staying the same" explain the children not re-rendering. I thought props changing does not cause re-renders anyways.
overall I really like your content but my brain is just finding it such a hard time to understand it.
It really is just a matter where the Element is created and where the state is triggered. When we pass elements as props to a component with state, those elements are created in the parent components. Something like this:
```
const App = ({ elemAsProp }) => {
const [state, setState] = useState();
// elemAsProp content won't re-render because of setState
return {elemAsProp}
}
```
Whatever is passed in `elemAsProp` won't be affected by the state change from `setState` in the `App` - they are higher in the components hierarchy. And when you pass components as `children` - it's exactly the same, they are just props in this case.
If, however, you create an Element inside the `App`, when state change is triggered and `App` re-renders, every Element declared inside will be re-rendered as well:
```
const App = () => {
const [state, setState] = useState();
// this one will re-render when setState is triggered
const elemInside =
return {elemInside}
}
```
It's described in more details here: www.developerway.com/posts/react-elements-children-parents
sir, you are madam??