Topics

SolidJS•6mo ago

Creating a store with data returned from an async function

Simplifying greatly, this is what I would like to achieve:

const [tab, setTab] = createStore({
    path: await homeDir(),
    view: await userPreferences.get("preferredView")
});

const [tab, setTab] = createStore({
    path: await homeDir(),
    view: await userPreferences.get("preferredView")
});

I understand there is no way to get the return result of an async function in top-level code (this is within a .ts file). Now I know some of you might suggest resources, however, I only need to use these async functions at app launch (aka once and never again), and they are all extremely fast (<10ms) so I do not need to use Suspense or add a loading indicator to my GUI. The only solution I can think of at the moment is initializing properties like path and view with "dummy" values and then within an async-friendly initialization point such as onMount, populating said properties with their real values fetched from the async functions. Using dummy values is a really crappy solution in my opinion so I would be so grateful if somebody had a neat solution to this issue. Coming from lower-level languages like Rust, the lack of control over synchronization drives me insane in these frontend frameworks. Thanks.

75 Replies

Brendonovich•6mo ago

You can use createResource and just not add Suspense, I'm pretty sure that will just stop anything from being shown until they're done.

Coming from lower-level languages like Rust, the lack of control over synchronization drives me insane in these frontend frameworks

To be clear, with Solid you have pretty much complete control over how you synchronize your data and UI. You're absolutely able to do homeDir().then(dir => setDirSignal(dir)) in onMount or something.

JOP•6mo ago

You can use createResource and just not add Suspense, I'm pretty sure that will just stop anything from being shown until they're done.

From the docs:

data() is undefined until fetchData finishes resolving.

So I imagine I would end up getting a ReferenceError using this strategy?

Brendonovich•6mo ago

Since you want to use those values to populate a store, I think I'd fetch them in createResource in a component above the createStore, and then use <Show> so that createStore isn't called until everything is loaded

function Wrapper() {
  const data = createResource(() => ...);

  return (
    <Show when={data()}>
      {data => <Inner initialData={data()}/>}
    </Show>
  )
}

function Inner(props) {
  const [tab, setTab] = createStore(props.initialData)
}

function Wrapper() {
  const data = createResource(() => ...);

  return (
    <Show when={data()}>
      {data => <Inner initialData={data()}/>}
    </Show>
  )
}

function Inner(props) {
  const [tab, setTab] = createStore(props.initialData)
}

JOP•6mo ago

I kind of want to isolate this data into a .ts file as it's global app data that will be used absolutely everywhere, including in functions in other .ts files You'll have to bear with me as I am coming from Svelte after not working with JSX or React in 2 years (with barely any experience even back then).

Brendonovich•6mo ago

Do you want homeDir or tab available globally?

JOP•6mo ago

I'll just provide you with a better simplified schema of the global state I want as my first example was not robust enough: src/app/state/index.ts:

const [tabs, setTabs] = createStore([
    {
        path: await homeDir()
        // ...Some other properties that may be loaded async such as data from disk
    }
])

const [tabs, setTabs] = createStore([
    {
        path: await homeDir()
        // ...Some other properties that may be loaded async such as data from disk
    }
])

Since I need each tab to be part of this array of tabs, I can't isolate specific properties into resources or signals, or at least, I'm not sure how I would integrate something like a Resource into a store... src/app/index.ts:

// Must be able to be accessed anywhere else in the application and this function must be able to access tabs from src/app/state of course
export function refreshTab(tabIndex: number) {
    // Omitted
}

// Must be able to be accessed anywhere else in the application and this function must be able to access tabs from src/app/state of course
export function refreshTab(tabIndex: number) {
    // Omitted
}

I'm using Tauri (I see that you're parting of the working group, neat!) and my application is pretty unique for a web framework like solid so it's hard to translate the expected web paradigms described in the docs into something that's usable for my app. I can't really just wrap things in components I need to be able to access this state from everywhere and I of course need it to be reactive.

Brendonovich•6mo ago

I think I'd do the same approach I described above and make tabs accessible via context, refreshTab can then take in the specific tab item as an argument instead of receiving the index and having to look it up itself Context and Suspense worked great for us building Spacedrive

JOP•6mo ago

Hmm, I'll have to switch up my design paradigm then I really appreciate the help!

Brendonovich•6mo ago

No worries, hope you get it worked out Also, you should be able to integrate resources into stores using getters

const [tabs, setTabs] = createStore([
    {
        get path() {  
          return homeDirResource()
        },
        // ...Some other properties that may be loaded async such as data from disk
    }
])

const [tabs, setTabs] = createStore([
    {
        get path() {  
          return homeDirResource()
        },
        // ...Some other properties that may be loaded async such as data from disk
    }
])

Ah nvm You can't overwrite path with this setup

JOP•6mo ago

Yeah One solution I've thought about is using the return value of createResource, then using the accessor and loaded things as usual, and using mutate to change it later But once again using a resource is pretty redundant after initialization

Brendonovich•6mo ago

This implies that the source of truth for path would be the resource, rather than tabs which seems wrong. Most of these sorts of problems can be solved by thinking about whether the source of truth for the data should be If you're gonna be reusing homeDir for new tabs then not really, you need somewhere to store it

JOP•6mo ago

What do you mean by "source of truth"?

Brendonovich•6mo ago

Like the place that dictates 'this is the values of this thing' With the getter example, even though tabs[0].path exists, the source of truth would be the resource you're mutating Which doesn't make sense since each tab should be the source of truth for its own path

JOP•6mo ago

I'm not a frontend dev at heart but what I'm hearing is that it's discouraged to wrap data in a Store within a Resource? Actually that does make sense because stores have their own proxying for reactivity

Brendonovich•6mo ago

I wouldn't say discouraged, rather it probably doesn't make sense to do so in a lot of cases And source of truths are relevant for the backend too, thinking about whether the source of truth should be some database, a piece of Tauri state, a value local to a function scope, or a remote machine

JOP•6mo ago

The fact that something as simple as using async code to initialize values in a store is such a complex thing in any framework is one of the reasons I really dislike doing frontend work :'/ So you could describe source of truth as just the true origin of the data?

Brendonovich•6mo ago

Yeah sure It's important to consider because down the line you're going to be doing transformations and derivations on that data, and if a modification is important you want to be applying it to the actual source of truth rather than some copy

JOP•6mo ago

Also I guess I meant the ambiguity around synchronization that comes with using frontend frameworks. In languages like Rust, it's very clear what order code takes place (ignoring async ofc but that's a whole nother can of worms).

Brendonovich•6mo ago

Doing something like let a = reqwest::get().await; is pretty much the same as the <Show> example I mentioned, since you're suspending the current future until the data resolves And if you wanted global state that came from an async source in Rust I feel like you'd have similar synchronization issues Like do you put it in a global static with OnceCell or Lazy, or a thread local, or have an optional field on a global struct and a task that receives from a channel and then updates the optional field, or no global at all and instead passing around some struct that has the prefetched data via function arguments

JOP•6mo ago

Well that is one hell of a sentence my friend

Brendonovich•6mo ago

added some commas haha

JOP•6mo ago

At this point I think I'm having bigger issues because I am used to having a pretty clear separation between data and the gui code that reacts to that data

Brendonovich•6mo ago

i mean what do you usually use?

JOP•6mo ago

Whether that's the right or wrong approach I may have to figure out Svelte I had this same issue with using async when creating stores and I ended up using the dummy data method I mean it did its job and the app works fine But it's not ideal and now that I'm trying out Solid to see if a rewrite in it would be beneficial I want to be as idiomatic as possible to avoid a bunch of refactoring pain in the future Biggest pain in the ass in svelte was the lacked of nested reactivity So you can imagine solid became pretty attractive

Brendonovich•6mo ago

From how I see it, you can't get around the fact that you either a) don't create the list of tabs until you have loaded the prerequisite data, or b) use that dummy data until you have loaded the proper data. It'll happen in both Svelte and Solid and is just par for the course of dealing with async data sources Having used svelte I also agree Solid is nicer haha

JOP•6mo ago

Yeah I'm hoping Solid is like Rust in that the DX and performance were given very deep thought There's a lot of holes in Svelte when you do anything past the basics and that really contrasted with Rust. Writing the backend was an absolute pleasure, but then came the frontend logic and it was just horrible in comparison. Thanks, I needed the reassurance that there wasn't a better way, I'll choose one or the other.

Brendonovich•6mo ago

Performance is absolutely a top priority, DX I'd say depends on what your're talking about. Solid provides a lot of primitives that let you build the way you want which could be a better DX if that's what you're into, but could also be harder if you're looking for a bit more hand holding

JOP•6mo ago

By great DX I mean this:

if let Ok(Some(val)) = result { 
    ...
}

if let Ok(Some(val)) = result { 
    ...
}

It's very rare I find myself writing what feels like redundant code in Rust (plus macros can supplant that a lot of the time) Lmao Yeah I'm willing to sacrifice ease of use for performance, we'll see how it goes

Brendonovich•6mo ago

How's this for you haha

<ErrorBoundary>
  <Show when={result()}>
    {val => ...}
  </Show>
</ErrorBoundary>

<ErrorBoundary>
  <Show when={result()}>
    {val => ...}
  </Show>
</ErrorBoundary>

JOP•6mo ago

Yeah I need some time to wrap my head around the JSX way of doing this after using Svelte for so long Anyways I really appreciate your help, made a big difference after dredging through the docs for so long. Have a good one @Brendonovich Another question, would it be possible to have a reactive Solid store that is also bidirectionally synced with a Tauri disk store?

createEffect(() => {
    for (const [key, value] of Object.entries(solidStore))
        tauriStore.set(key, value);
});
this.diskStore.onChange((key, value) => {
    // @ts-ignore
    setSolidStore(key, value);
});

createEffect(() => {
    for (const [key, value] of Object.entries(solidStore))
        tauriStore.set(key, value);
});
this.diskStore.onChange((key, value) => {
    // @ts-ignore
    setSolidStore(key, value);
});

The code I prototyped above looks like it would produce an infinite loop...

Brendonovich•6mo ago

if tauriStore.set triggers diskStore.onChange then yeah that'll cause an infinite loop haha Is the source of truth in this case the Tauri store, and the UI is just a reflection of it, or the UI store, where the Tauri store is just a backup? Bc in the latter case I think I have an easy solution for you

JOP•6mo ago

Sorry, source of truth is for sure the Tauri store Reason being I need to share this state between windows and have it automatically update the UI

Brendonovich•6mo ago

In that case I don't think i'd have the createEffect I think i'd directly update the tauri store, and have the UI store be updated later by diskStore.onChange

JOP•6mo ago

How would I subscribe to changes on the Solid store then?

Brendonovich•6mo ago

And if you wanted the UI to update immediately you could write directly to the store, which would then get overwritten by diskStore.onChange Basically the same as doing optimistic updates with an http api

JOP•6mo ago

I don't really want to manually write setters for every property My hope was that I could create a catch-all that would avoid boilerplate

Brendonovich•6mo ago

Wym setters for every property? You already have to write bindings for each field to the UI

JOP•6mo ago

Yeah, I'd like to be able to just assign a property in the Solid store and have that change reflected in the Tauri store Not sure how binding works in Solid, haven't looked into that yet give me a minute to check the docs

Brendonovich•6mo ago

By bindings i mean onInput handlers and stuff

JOP•6mo ago

Is there no equivalent to something like svelte's bind:value on an input?

Brendonovich•6mo ago

Nah

JOP•6mo ago

Shit

Brendonovich•6mo ago

Solid is simple, not easy lol

JOP•6mo ago

What's the reasoning behind that?

Brendonovich•6mo ago

https://github.com/solidjs/solid/discussions/619#discussioncomment-1224573

GitHub

Proposal: consider using 2-way bindable structures. · solidjs solid...

I know that, this might sound as a paradigm change, however inspired by this library, I've created a poc library for 2-way bindable structures, that might be considered for solid: This would ch...

Brendonovich•6mo ago

one-directional data flow > two way bindings in solid land

JOP•6mo ago

Yeah that figures I've had some nasty bugs arise from two way flow

Brendonovich•6mo ago

Here's something that might work

import { makePersisted, tauriStorage } from "@solid-primitives/storage"
import { Store } from "@tauri-apps/plugin-store"

const store = new Store(NAME)

const [state, setState] = makePersisted(
  createStore(),
  { storage: tauriStorage(NAME) }
);

store.onChange((key, value) => {
  setState(key, value)
})

import { makePersisted, tauriStorage } from "@solid-primitives/storage"
import { Store } from "@tauri-apps/plugin-store"

const store = new Store(NAME)

const [state, setState] = makePersisted(
  createStore(),
  { storage: tauriStorage(NAME) }
);

store.onChange((key, value) => {
  setState(key, value)
})

JOP•6mo ago

Only issue with one way is that it won't reflect on another window when it's changed A prime example being 2 windows with a settings page open on each Aha! Fantastic I thought somebody else might have thought of this before

Brendonovich•6mo ago

Sure it will, if a value in one window's store changes then it'll trigger onChange in the other window and update that window's store, which will rerender the UI makePersisted intercepts the setState call rather than using an effect so you don't have the infinite loop problem

JOP•6mo ago

Not if it's setup like this <input value={store.preference} onInput={(event) => store.preference = event.target.value} />

Brendonovich•6mo ago

I'd just watch out for synchronisation issues, one window's state will update instantly while the others lag behind sure it will

JOP•6mo ago

ah i'm trippin

Brendonovich•6mo ago

also do setStore('preference', event.target.value)

JOP•6mo ago

yeah ofc that's just my svelte brain talking

Brendonovich•6mo ago

lmao unless you use createMutable

JOP•6mo ago

I've heard pretty bad things about createMutable lol include makes it easy enough either way

Brendonovich•6mo ago

if your data is a tree it's great otherwise avoid it

JOP•6mo ago

When wouldn't it be? You mean arrays v objects or sumthn?

Brendonovich•6mo ago

I more just mean highly nested data, which trees tend to be. Passing down the setter and calling it properly can get annoying in those cases Recursive data especially, since you have to design your components to work infinitely nested

JOP•6mo ago

Wait, avoid include or createMutable?

Brendonovich•6mo ago

createMutable haha

JOP•6mo ago

Okay good So there's no real downside of just putting in the little extra work required for using a store/signal over createMutable right?

Brendonovich•6mo ago

If you want to avoid the footguns that createMutable can add then yeah

JOP•6mo ago

It appears that @solid-primites/storage has a sync api but it doesn't seem that they have tauri integrated with it

Brendonovich•6mo ago

import { tauriStorage } from "@solid-primitives/storage/tauri" got it wrong the first time

JOP•6mo ago

With messageSync, you can recreate the same functionality for other storages within the client using either the post message API or broadcast channel API. If no argument is given, it is using post message, otherwise provide the broadcast channel as argument

I wonder if this works between windows with Tauri... I doubt it

Brendonovich•6mo ago

tauriStorage uses @tauri-apps/plugin-store under the hood

JOP•6mo ago

I'm aware I was ~~rawdogging~~ it before with svelte

Brendonovich•6mo ago

Oh i thought you'd already implemented the onChange part Oh nvm that does exist

JOP•6mo ago

I was just wondering if that might cause an infinite loop as well. I don't really know how it works under the hood. Wdym

Brendonovich•6mo ago

Ohh i get u Looks like set will trigger onChange in the same window

JOP•6mo ago

bummer

Brendonovich•6mo ago

Good thing makePersisted is a wrapper around the setter

import { makePersisted, tauriStorage } from "@solid-primitives/storage"
import { Store } from "@tauri-apps/plugin-store"

const store = new Store(NAME)

const [state, setRawState] = createStore();
const [_, setState] = makePersisted(
  [state, setRawState],
  { storage: tauriStorage(NAME) }
);

store.onChange((key, value) => {
  setRawState(key, value)
})

import { makePersisted, tauriStorage } from "@solid-primitives/storage"
import { Store } from "@tauri-apps/plugin-store"

const store = new Store(NAME)

const [state, setRawState] = createStore();
const [_, setState] = makePersisted(
  [state, setRawState],
  { storage: tauriStorage(NAME) }
);

store.onChange((key, value) => {
  setRawState(key, value)
})

JOP•6mo ago

I'll give that a try later Giving a new framework a try this late at night was a bad idea

Solid is a declarative reactive Javascript library for creating user interfaces.

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