Challenges with StateView and Nested Schema Structures

[AndadH]

I've implemented a player inventory system using @view() to reduce network traffic, but I'm encountering issues with client-side visibility of nested schema objects.
My current implementation:

 //Player class with @view()-tagged inventory
class Player extends Schema {
    // Other player properties...
    
    @view() @type(Inventory)
    inventory = new Inventory();
}

// Inventory contains a MapSchema of items
export class Inventory extends Schema {
    @type({ map: InventoryItem })
    slots = new MapSchema<InventoryItem>();
    // Other inventory methods...
}

// Room setup
onJoin(client: any, options: any, auth: any): void {
    const player = new Player(client.sessionId, ...);
    this.state.players.set(client.sessionId, player);
    
    client.view = new StateView();
    client.view.add(player);
    client.view.add(player.inventory);
    client.view.add(player.inventory.slots);
    // Items in inventory.slots aren't visible to the client
}

The issue:
While I can see other player properties, the inventory and its contents aren't visible on the client side. Based on the documentation about MapSchema with StateView, I understand I may need to add each item in the slots MapSchema individually.
Questions:

1. What's the recommended pattern for handling deeply nested schema objects with StateView?
2. Is there a more efficient way to selectively sync inventory data without manually tracking every item addition/removal in the StateView?
3. Are there performance considerations I should be aware of when using StateView with frequently changing collections?

Any guidance would be greatly appreciated!

[endel]

Hi @AndadH, that's correct... When calling view.add(), its current items will be added to the view (and it does so recursivelly, just client.view.add(player) would suffice at the setup).

New items need to be added manually. So you would add the item to the state, and then to the StateView:

const helmet = new Helmet();
player.inventory.slots.set("helmet", helmet);

view.add(helmet); // add this item to the user's state view

Regarding removals - it should be enough to remove them from the state only - removing from the StateView is optional as we're using a WeakSet internally and they should be garbage collected.

player.inventory.slots.delete("helmet");

The StateView is still new and I'm getting feedback from its usage... The actual implementation is not perfect but I believe it can be optimized and improved from there.

Is there a more efficient way to selectively sync inventory data without manually tracking every item addition/removal in the StateView?

I'm open to suggestions here. I think the current way using view.add() and view.remove() is fairly straightforward.

Are there performance considerations I should be aware of when using StateView with frequently changing collections?

The more data you put into @view() tag, the more the server will spend encoding data for particular players. Each player view introduces a new encoding step. I'd recommend using it as minimal as possible. I haven't benchmarked it with big amounts of data yet...

I hope this helps! Let me know if this works for you 🙏

[AndadH]

Oh sorry, you are totally correct. Still is there a better method?

[Nul-led]

Oh sorry, you are totally correct. Still is there a better method?

Better method.. hm probably not. StateView uses weaksets/maps so in theory its already as efficient as it can be since it would only store a weakref to the object which is pretty much just 2 ptrs. So memory wise this is a lot more efficient than using cbs / pub sub. Not sure about actual speed since there would be a lot of factors but i feel like it would most likely be on par with pub sub.

[AndadH]

okay, that makes sense. So I were adding all 50+ slots of each players inventory to their view do you think that would cause preformance issues?

[Nul-led]

I mean i cant say for sure. You would need to do some testing yourself, but i can say that i have ~3k objects synced through stateview and i dont see any noticable performance issues.

[AndadH]

okay that actually helps a ton, thank you for your help!