shadaj/slinky

Everything about Slinky -- issues, ideas for features, where it's being used, and more

Peter Storm

@peterstorm

Ah gotcha

Thanks

Gabor Juhasz

@gjuhasz86

Is there a way for functional components to expose methods for their parents? I just finished rewriting all my components to functional, and realized that the next step requires this.

Alexis Hernandez

@AlexITC

that's against react good practices,isn't it? I suggest to came up with a better design

Gabor Juhasz

@gjuhasz86

yeah, it just seems like however I try, encapsulation in general is against react's good practices

Alexis Hernandez

@AlexITC

I think that's part of the unidirectional-flow design, if you post what you are trying to do, or a code sample, I can try to come up with an alternative approach

Gabor Juhasz

@gjuhasz86

Thanks, I'm working on a small scale example, almost finished

Gabor Juhasz

@gjuhasz86

@AlexITC Ok I think I have something
https://scalafiddle.io/sf/A6u6PzL/0

so we have the component Panel that can do some operation on two numbers

This is self contained and works as expected.

Now I want to create a bunch of Panels and define linkage between them (dynamically), so that the one panel's output is piped to the other panel's first input.

Alexis Hernandez

@AlexITC

Without looking at the code, this is what I'd do, for each panel, define a function that gets invoked when the panel is updated, which you take from the parent component to update other panel's props, which would trigger such panels to be rendered again

Gabor Juhasz

@gjuhasz86

so basically you're saying that I should hold all the state of the panels in the parent, and pass them as props

and whenever I want to update them from inside the panel, I should invoke the callback, provided by the parent

Alexis Hernandez

@AlexITC

yes

Gabor Juhasz

@gjuhasz86

right, that's where I get suspicious about encapsulation.
Because it's not just the state itself, but also all the logic of how to modify it has to be lifted up to the parent. And I will end up with all the state and all the logic in the outermost component.

Not to mention the "loop" which is another pain point, I don't like the index-based addressing even in this solution

Alexis Hernandez

@AlexITC

you could propagate some state through the props to the panels, and each panel can choose if it is worth to do anything, instead of keeping the logic on the parent

Gabor Juhasz

@gjuhasz86

right, that's true

Gabor Juhasz

@gjuhasz86

ok then looking at this from a bit of a different angle: is there a way to keep the state in the parent, pass it to the children as props, but when the children wants to change it, it wouldn't have to call back to the parent who has to provide the exact way of how to change the state?

Gabor Juhasz

@gjuhasz86

I have the feeling that maybe its possible with redux... But I'd like to avoid spending another 2 weeks on a dead-end, so I'm interested in any suggestion

Alexis Hernandez

@AlexITC

I know two ways, you send the argument, or how to retrieve it, in the later case, you can share an object holding a var, which can be mutated, but I think that's a worse idea

Gabor Juhasz

@gjuhasz86

can you show me an example for "sending the argument"?

Alexis Hernandez

@AlexITC

just send such argument in the panel's props

Gabor Juhasz

@gjuhasz86

I mean I can do something like this:

val (nums, setNums) = useState(List((1,2),(3,4)))
nums.map{ p=> Panel(p) }

so far so good, but then I'd like each Panel to be able to change its own props

but that gets messy

Alexis Hernandez

@AlexITC

I'd invoke the useState on each panel's mutable state, and invoke the props callback when such state gets updated

Gabor Juhasz

@gjuhasz86

I'm sorry I don't see how that achieves what I want/ But anyways, it's late, I might give it another try in the morning (not too optimistic, though)

thanks for your help

Peter Storm

@peterstorm

Does anyone have an example with the ContextAPI in SLinky?

Gabor Juhasz

@gjuhasz86

So I was finally able to hack around the problem I had with calling into functional components. I'm passing in an observable using scala.rx. I guess it's still a hack but I didn't feel like rewriting the whole app again in a different framework.
Here's the code from before reimplemented with functional components and scala.rx in case anyone's interested: https://pastebin.com/DnLHpnZ8

Peter Storm

@peterstorm

Hmmm, cant seem to get useContext to work, when doing this:

package connect.ui.components.auth

import slinky.core._
import slinky.core.annotations.react
import slinky.web.html._
import org.scalajs.dom
import slinky.core.facade.{Fragment, ReactElement}
import slinky.web.ReactDOM
import slinky.core.facade.React
import slinky.core.facade.Hooks._
import typings.reactRouterDom.{ components => router}

import scala.scalajs.js

import connect.ui.domain.authentication.Auth
import org.scalablytyped.std.global.console


@react
object AuthContextProvider  {

   val authContext = React.createContext[Auth](Auth(false, "", "", 0, () => ()))

  case class Props(test: String, children: ReactElement*)

  val component = FunctionalComponent[Props] { props =>

    val (isAuthenticated, setIsAuthenticated) = useState(false)


    def loginHandler(): Unit = {
        console.log("loginHandler called")
        setIsAuthenticated(true)
        router.Redirect(to = "/")

    }

    authContext.Provider(value = Auth(isAuthenticated, "", "", 0, loginHandler _))(
        props.children
    )

  }
}

If i then useContext(AuthContextProvider.authContext) in a different component

It only uses the initial context i provided

But if I do AuthContextProvider.authContext.Consumer( context => ...) it works

Peter Storm

@peterstorm

I tried to use it in the App componenet, but that didnt make too much sense

So apologies, it works perfectly well in nested components :)

Sina

@sinaghaffari

Any alternatives to slinky-styled-components since that hasn't been released for Scala 2.13?

Peter Storm

@peterstorm

Does Slinky support React.lazy and Suspense?

Peter Storm

@peterstorm

Ah, suspense i can see. and I can use suspense without lazy, right?

Pascal Mengelt

@pme123

Hi there, I created 2 examples:
A Simple Example using Slinky with a Scalably Typed example (Plotly & Ant Design).
https://github.com/pme123/scalably-slinky-example
The famous TODO List as a client-server example with Slinky.
https://github.com/pme123/slinky-todos

nafg

@nafg

Is Slinky already being ported to scala 3? If not, what is the plan?

Shadaj Laddad

@shadaj

@peterstorm yeah, you can use suspense with a couple libraries (Apollo Client comes to mind); I do hope to get lazy working soon, once the bundle splitting support in Scala.js stabilizes

@pme123 that's awesome! Do you mind creating a PR to add those to https://slinky.dev/docs/resources/ ?

@nafg not as of right now, I haven't explored the state of Scala.js and the associated tooling in Scala 3 too much now. I don't expect there to be too many issues getting the Slinky core, minus @react working, since the remaining macros are mostly just for typeclass derivation.

Pascal Mengelt

@pme123

@shadaj you already merged it;)

mn98

@mn98

@pme123 thanks for sharing those sample projects, they'll be very helpful!
I've been using Slinky with Play and scala-js to handle all the routing/client-server interaction, to good effect. Out of curiosity, are there any reasons why you took smaller components rather than a framework such as Play? If this is too off-topic please feel free to PM me if you wouldn't mind. Thanks!

Pascal Mengelt

@pme123

@mn98 I use Play for my work - so in my freetime I try mainly stuff that interests me and could be an option for a future project at work - so in case of http4s it is the functional part that interests me;).

Peter Storm

@peterstorm

Play is way too opinionated imo, we use http4s at work too, for our admin interface, also made with Slinky

mn98

@mn98

@pme123 @peterstorm thanks, both! I'm toying with moving to http4s anyway, so might give that a shot.

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