[Aeolun]

But what does ‘#await someFetch’ actually do? The thing I like most about react is that it’s just executing plain Javascript most of the time.

[dmitriid]

> The thing I like most about react is that it’s just executing plain Javascript most of the time.

Then explain what hooks do ;)

Hooks are decidedly not Javascript (even if they look like Javascript), and are a much more weird construct than {#await promise}

[_hzrk]

No, they are JavaScript, it is array based programming wrapped in a reactive functional-declarative approach. Simply array of objects cascading with state. {#await promise} is more cryptic than any useHook function implementation.

[dmitriid]

> No, they are JavaScript, it is array based programming wrapped

Javascript has no support for array-based programming.

So, hooks are not Javascript: they look like regular function calls, but:

- they can only be declared and called before rendering

- they can't be called out of order

- they cannot be called conditionally

- they have to be called a specific name to be handled correctly by React runtime

- some (but not all of them) require dependency lists that determine how they are invoked

> {#await promise} is more cryptic than any useHook function implementation.

usEffect documentation is something like 20 pages long. The use of {#await promise} is immediately understandable from the code example, and its entire documentation fits on a page and a half

[Aeolun]

They are definitely javascript. I can click to definition of the useEffect function and see exactly what it is doing.

I completely agree that learning them is a bit crazy, but ultimately every hook comes down to being a function execution.

[dmitriid]

> They are definitely javascript.

How come they break Javascript semantics and execution flow?

> but ultimately every hook comes down to being a function execution.

That's really beside the point when it comes to understand what something is and using them.

{#await promise} is immediately understandable from its use.

Hooks are... well, I already said above.

[merb]

> How come they break Javascript semantics and execution flow?

wait what? since when do they break execution flow and javascript semantics?!

useEffect(function () { }); when exactly do you think the function will be called? - correct only the "framework" defines that, but that's completly normal javascript execution and semantic.

[noir_lord]

https://svelte.dev/tutorial/await-blocks Explains it better.

[hunterb123]

His point is you don't have to read some project's documentation to know how some "await blocks" work.

With JSX you can use native JS features instead, you only need to know the language.

For example, instead of looking up how to loop in the template syntax, you use an iterator.

[noahtallen]

Not just most of the time — all of the time! JSX is converted to plain JS (react.createElement) before it gets to the browser.

[tuukkah]

Isn't it actually the opposite? Svelte code is compiled to plain JS whereas React has a large runtime.

[Aeolun]

Nah, JSX also gets converted to Javascript. The difference is in that the React runtime re-renders whole components every time something changes, and Svelte is more granular about it even during the compilation step.