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@filter not working as expected

  • My GameState has a map (MapSchema) of players (Player). Inside Player, I have a field which should be private (visible to the player and not the entire room). I am trying to use @filter, but without success.

    export class SecretSchema extends Schema {
        xyz: number;
        abc: number;
    export class Player extends Schema {
        @filter(function(this: Player, client: any, value: GameMap, root: GameState) {
                return true;
        secretVar: SecretSchema;
    export class GameState extends Schema {
        @type({ map: Player })
        players = new MapSchema<Player>();

    First, I have typescript errors on @filter. It says that Player and Schema are incompatible. But apart from that, "filter" is not printed to the console and I get the whole state on all Players in the room.

  • administrator

    @emarkk filters are not working yet, they're exposed but they don't really work, I'm going to remove it in the next version until we can actually use them

  • Ok, I get it. The same goes for @nosync?

  • administrator

    @nosync is for FossilDelta only, it has no effect using the Schema serializer

  • Has this been fixed ? I am trying to use Filters to hide other players Hand in a card game but I face an issue

    Firstly, I get typescript error saying Schema of Value does not match
    Argument of type '(this: PlayerTurn, value: ArraySchema<Card>, client: Client, root?: GameState) => boolean' is not assignable to parameter of type 'FilterCallback<PlayerTurn, Schema, GameState>'.
    Types of parameters 'client' and 'value' are incompatible.
    Type 'Schema' is not assignable to type 'Client'.
    Type 'Schema' is missing the following properties from type 'WebSocket': binaryType, bufferedAmount, extensions, protocol, and 32 more.ts(2345)

    If i change the value to the Type itself, the filter is never invoked.

  • administrator

    Hi @meetsreekanth, filters are experimental right now, but it should work for the use-case you've just described.

    I think the order of your parameters is not correct, the filter callback type looks like this:

    export type FilterCallback<
        T extends Schema = any,
        V = any,
        R extends Schema = any
    > = (this: T, client: Client, value: V, root?: R) => boolean;

    It's also important not to use arrow functions on filters, so this should work:

    @filter(function (this: PlayerTurn, client: Client, value: ArraySchema<Card>, root?: GameState) {
      return // ??

    Hope this helps, cheers!


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