Class Store<TState>

Namespace: Velvet

Assembly: Velvet.Docs.dll

State container: immutable state plus collocated actions in a single class, with synchronous subscribers notified on every change.

public abstract class Store<TState> : IStoreWriter<TState>

Type Parameters

TState: Immutable state record type.

Inheritance: object

Store<TState>

Implements: IStoreWriter<TState>

Remarks

Equivalent to a Zustand store for users migrating from Zustand.

Threading: a store is single-threaded. All reads, mutations (SetState(Func<TState, TState>) / Mutate(Func<TState, TState>)), and subscription changes must occur on the Unity main thread (PlayerLoop). The store performs no internal locking; it assumes a single-threaded model.

Re-entrancy: listeners passed to Subscribe(Action<TState>, bool) / Select<T>(Func<TState, T>, Action<T, T>, IEqualityComparer<T>?, bool) must not synchronously mutate the store. Notification is synchronous and not serialized, so a re-entrant mutation interleaves delivery and can reorder the (current, previous) pairs seen by other subscribers. Defer such updates (e.g. via a scheduler / next frame) instead of mutating during notification.

Constructors

Store(TState): Retains initial as InitialState and seeds the live state with it.

Properties

CancellationToken: CancellationToken for async operations.

Current: Snapshot of the current state.

InitialState: The state value the store was constructed with. Useful for distinguishing "untouched" from "user-modified" without separately tracking a dirty flag, and for diffing against the persisted/seed value.

Logger: Logger. null suppresses logs.

Methods

Dispose(): Releases resources in the order: CTS cancel → state notifier.

Mutate(Func<TState, TState>): Updates state unconditionally. Used for cases like Reset where notification must always fire.

OnDispose(): Subclass-specific dispose logic (overridable). The state notifier is already disposed at this point and must not be accessed. Subscriptions a subclass opened via Subscribe(Action<TState>, bool) / Select<T>(Func<TState, T>, Action<T, T>, IEqualityComparer<T>?, bool) are owned by the subclass and should be disposed here.

Reset(): Resets state to the initial value. Non-virtual template method that short-circuits when the store has been disposed; concrete stores implement ResetCore().

ResetCore(): Concrete reset logic. Called by Reset() only when the store is not disposed.

Select<T>(Func<TState, T>, Action<T, T>, IEqualityComparer<T>?, bool): Subscribes to a selected slice with a (currentSlice, previousSlice) signature. The listener fires only when the selected slice changes under the given comparer.

SetState(Func<TState, TState>): Updates state (equality-checked).

Subscribe(Action<TState, TState>, bool): Subscribes to state changes with a (current, previous) signature.

Subscribe(Action<TState>, bool): Subscribes to state changes.

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