Відео

I need some hard evidence. Is there a performance hit using const vs let? Is the mutable content of array and objects his only issue? Const is just saying a pointer can’t be reassigned.

Mean while the actual programmers here that don't use a toy language have real things to talk about. This is sad and ridiculous

I’m curious what extension is being for code completion here?

for (const i...) is probably the only thing that bothers me logically. It's a constant that... changes?

How is this a controversy? Const means the reference? I.e. the reference is constant, and it can't be reassigned? Look to Java - final refers to the reference, and then you have immutable/unmodifiable collections which are different.

When your arguments are so weak you fake LLM responses.

There's also a typo in Ryan's "ChatGPT response"... :D

Why are veteran programmers confused about a value of an immutable binding. Variable in a math sense.

React as a library and its ecosystem with all frameworks has blown out of proportion. It is supposed to be an unopinionated library, yet it sets rules and provides hooks which make everything confusing. I would prefer React to be a framework which is very strict on best practices and doesn't allow writing "bad" code in the first place. And what is "well-written" React anyway? It is extremely difficult to write React code that doesn't smell. The new React documentation attempts to address some of the anti-patterns, but sometimes fails to provide good solutions. Out of all of the frontend tools, I prefer Angular the most, since it has a clear philosophy with clear best practices and doesn't allow you to opt out of the paradigm easily. Many frontend engineers lack training in computer science and software engineering. They only learned the basics of JavaScript and jumped straight into React. React should be better at providing directions for what good code is and what bad code is. React fails at this completely. The worst code smell in React is the useEffect hook. It is ironic that they recommend using it as little as possible, yet it is likely the second most frequently used hook after useState. That says a lot about the bad design decisions that the React team have made over the years. It is a bit sad that an entire industry has invested immensely in a frontend tool which is very poorly built if you look at it from an engineering angle.

how do i add react to a web component?

Not sure if this is a dumb question. But I got a question about prod deployment. Let's say a host app use a component from remote app. This component has changed the props, e.g. add a 'name' props and delete a 'email' props. So obviously I will update both host and remote app. But during prod deployment, which I assume we will deploy remote into S3 first, does it mean the host will have a brief time of error on the component until we finish host app deployment? Of course, we can use error boundary to wrap the host app. But still, would be good to be somehow avoid the down time.

Sounds like a good reason not to use JavaScript.

Hi Jack! Can you redo this video but with the create-t3-app? That would be a banger, no?

Great content. I will try it out next week. It will help me a lot with the HTML of a platform that I am building

Which extension is used here to highlight components which are rerendered?

But whatever it is.. compiler version will increase production build i guess. 😢

"clean coders" pushing their unfounded opinions again. programmers need to stop wasting time on this vibe based mumbojumbo. or atleast present when something is valid and when it is not, not just go black and white "this is always bad to do" or "this is always good to do"

Thanks, I didn't know about const considering as a constant. Talk from the referenced video was not good. I stay with const.

Const is variable if you write anything that nests more than once... It also avoids juniors confusing scope so they can just work and practice reading, letting patterns sink in over time. Let is useful, const is useful, what isn't useful is var. Nothing useful about var except confusion. If a person says con instead of const, nobody would misunderstand. Horrible talk.

And once this "feature" is released, you can look forward to the next major React release that introduces a new "feature" to work around all the bugs this "feature" causes :) You React people are so silly.

I think, that actually the ability to mutate const value is a very strong argument. I use const a lot, but to be honest I always see a code smell when looking at const in cycles (where const is not const at all), and when constant object are being mutated. The REAL const is just a simple value which can be calculated one time before program started, and does not change every time you run your code (until you change your source code). For such values programmers often use UPPER CASE. like const MY_CONSTANT = 123. (I believe Ryan is talking about this case). You should always be able to replace your real constants (while building project) with real values. If not, then it's not a constant. Anyway, const keyword in javascript is still useful. Maybe it would be proper to rename it to something like "partially immutable" or "not directly re-assignable" not to confuse programmers. But it's too long, so keyword "const" for such variables is somewhat acceptable.

So project React Forget "MobX" has finally released their 300kloc+ monster of a horse pill "compiler". The industry is moving towards "signals" so why isn't React being made more officially pluggable with external reactivity systems? Why on earth would they spend this much time and money to release such a monstrosity on the world?! Legacy code. This is designed for "quick" wins on absolutely horrifying legacy code bases that are permanently moored in hook hell. Frankly I wouldn't be surprised if a lot of the industry decides to NOT get tangled up with this thing.

It was a great talk with several excellent points, I just wish he also addressed the issues with the 'class' keyword in Python. First of all, Python does not require that you declare variable types, therefore having to write 'class' does not fit with this ideology. Secondly, my cat cannot pronounce 'class' properly. I hope one day we will have a language that is written only in easy to pronounce words that can be correctly pronounced by both humans and cats alike.

Thanks for shedding some light on how this compiler works. The more I read about updates in the React world, the more I believe that this tool is overengineered. Frontend engineering should not have to be this complicated. It is only meant to be a UI library. Building a user interface should be quite trivial.

or Ryan's all talks was satirical.

🎯 Key Takeaways for quick navigation: 00:00 *🚀 React wprowadza własny kompilator, co czyni go jednym z najbardziej zaawansowanych kompilatorów wśród frameworków front-endowych.* 01:08 *🔄 Dzięki kompilatorowi React, tylko zmienione komponenty są renderowane ponownie, co zwiększa wydajność bez dodatkowego wysiłku ze strony programisty.* 01:51 *📅 Chociaż kompilator jest w fazie rozwoju, produkty Meta jak Instagram już go używają.* 03:20 *🧩 React Compiler automatycznie zarządza pamięcią i referencjami, eliminując potrzebę użycia useMemo i useCallback w wielu przypadkach.* 05:13 *🧠 Nowy hook useMemoCache pozwala kompilatorowi na efektywną pamięć podręczną elementów JSX.* 06:38 *🔍 Kompilator potrafi usuwać niezmienne wartości, takie jak stałe, i wstawiać je bezpośrednio do kodu JSX.* 08:00 *🔄 Kompilator inteligentnie zarządza dynamicznymi elementami, aktualizując tylko te, które wymagają zmian.* 10:57 *🛠️ Jeśli kompilator napotka nieoptymalny kod, powraca do oryginalnego transpileru bez prób optymalizacji.* 11:39 *🕒 React Compiler pomaga stabilizować referencje w tablicach zależności hooków useEffect, co rozwiązuje wiele typowych problemów.* 13:04 *📝 React 19 nie zawiera kompilatora, ale warto już teraz zacząć eksperymentować, aby być gotowym na jego stabilną wersję.* 13:34 *⚠️ Kompilator nie współpracuje z MobX z powodu fundamentalnych różnic w zarządzaniu stanem opartym na proxy.* 14:30 *🌟 Nowy kompilator otwiera drzwi do dalszych optymalizacji, takich jak różne modele renderowania oparte na układzie komponentów.* Made with HARPA AI

I'm just slightly confused... first "react forget" was the big hype of React 19 release but now we have "compiler" and that is supposedly NOT coming in React 19? is react forget now called compiler or are those two separate features?

i could see using var for callbacks, the problem is the scope is functionally different. I see no issues setting const to a function or a callback. although if it's an imperfect function, it does seem a bit strange. Listening to this take makes me think a bit more about how intentional i can be, but for the most part, i'm in agreement with you. the talks a bit click baity and too much of a hot take to be considered seriously

I was confused about the let vs const debacle. I always think like this: I'm declaring a variable for a purpose, will I ever need to change what its pointing to (reassign it)? If yes, then let's use let (maybe I'm doing a sum or an avg without a loop), if not, let's use const (I may just need a way to make sure I'm using the same reference from when I declared it). If I'm using objects or arrays and I need the content to remain the same always, then I use Object.freeze. But that has nothing to do with let or const

working with JS for 2 decades now and since we had const I never faced any issues that he is describing... I am not sure why we are discussing this... is that lack of drama in JS world ?

I really wish there were a better way to do all this, as it's quite a lot of boilerplate. Especially the part where you need to re-stringify the FormData to pass down the fields from the server if zod validation fails. For example, what if a field is of a numeric or boolean or some other type? Ideally you shouldn't have to convert those types yourself. You already have a zod schema, so it would be nice to reuse it. I've been tinkering with Svelte's superforms library and it's phenomenal. It gives you all of this for free, and it works with and without JS. Plus you get inline errors and auto-populated field data from the server. The only downside is that it only supports method="POST".

This talk really annoyed me. It's an old rehashed argument we left behind like 9 years ago. Const obviously has value or it wouldn't have gained any traction. There is a difference between mutability and re-assignment, which this talk totally glosses over.

I see that you are a Godzilla/Gojira fan too!

your videos are very insightful and I always learn some new things

7:23 lol frontend devs getting introduced to compilers for the first time in their lives 🤣

your experience really helps us with such things. I hadnt seen the original talk but thanks for covering this! and true he didnt provide any compelling reasons so makes one wonder why even talk about it. didnt provide much value other than this video about critical evaluation of others 'opinions' to decide whether it makes sense for your purpose

Thanks a lot. Perfect like ever.

All I use is const, const, const no matter what

**EDIT** Does it compile the react code and while building is the React vendor/dependency opted-out from the final production bundle like Svelte?

Ecmascript 2034; const mut animals = []; 😏

thanks! your to the point tutorials are perfect! :D

Love seeing you shining a light on our industry BS.

Ouch

Excellent video lesson, loved it

This is huge! I am somehow worried but I think the compiler is great but I also think it takes alot from beginners where you have to learn that this can't work if the ref is changing and why it's changing. Also we need to keep in mind that there is a bunch of stuff happening in the background I'd say because react was and still is just JavaScript using all its rules but now some things get hidden so some could get a dumb down effect where they will wonder why its not working. So we need to encourage people to still write good structured code I think this will benefit my react native projects too. I am worried that too much caching might push the memory usage of the apps but I think it will be fine as its only for the mounted states and pointing to something is just fine.

The examples with modifying the array are laughable. If you really wanted immutability you could use specific tools like immutable.js or immer.js to manage updates. I think this presentation is geared towards junior devs trying to grab on new ideas.

Thanks, but there are one point that have not appeared, the performance impact and specially when the memorization the components

I would have expected something about performance, memory management, or something technical. Its like people tell me to use function expressions instead of function declarations. If i start off using const, for the sake of consistance I will use it in my projects.

// @ts-check /** @type {import('next').NextConfig} */ const nextConfig = { experimental: { reactCompiler: true } } module.exports = nextConfig Use ‘next@canary’

How are you getting the boarders to show when state changes?