build(spf): build26 from 45504a2b

dist/dev/core/composition/create-composition.d.ts

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+import { ReadonlySignal, Signal } from "../signals/primitives.js";
+//#region src/core/composition/create-composition.d.ts
+/**
+ * Cleanup returned by a behavior. Behaviors may return:
+ * - `void` / `undefined` — no cleanup needed
+ * - A function — called on destroy (may return a Promise)
+ * - An object with `destroy()` — called on destroy (may return a Promise)
+ */
+type BehaviorCleanup = void | (() => void | Promise<void>) | {
+  destroy(): void | Promise<void>;
+};
+/**
+ * A signal map keyed by the fields of `S`. Each field is a writable signal.
+ *
+ * Optional fields on `S` map to required signal slots whose value type
+ * includes `undefined`, ensuring every key has a signal even when the
+ * underlying value is absent.
+ *
+ * Used in two roles:
+ * - Engine-side **construction**: `Composition<S, C>` exposes its public
+ *   surface as `StateSignals<S>` (everything writable) so external code
+ *   can read or write any slot.
+ * - Behavior **input convenience**: a behavior that writes to every slot
+ *   can type its setup state param as `StateSignals<{ ... }>` rather than
+ *   spelling out per-slot `Signal<T>` types.
+ *
+ * Behaviors that mix read-only and writable slots type the setup param
+ * directly as a slot map (`{ x: Signal<T>; y: ReadonlySignal<U> }`)
+ * instead of going through `StateSignals<>`.
+ */
+type StateSignals<S extends object> = { [K in keyof S]-?: Signal<S[K]>; };
+/**
+ * A signal map keyed by the fields of `C`. Each field is a writable signal
+ * for a platform object or actor reference. Same dual role as
+ * `StateSignals<S>` — see its docblock.
+ */
+type ContextSignals<C extends object> = { [K in keyof C]-?: Signal<C[K]>; };
+/**
+ * Slot-map shape — a record where each value is at least a `ReadonlySignal`.
+ * `Signal<T>` is structurally a subtype of `ReadonlySignal<T>` (it adds
+ * `.set()`), so a writable slot satisfies this bound too.
+ *
+ * This is the bound used for behavior `state` / `context` slot maps. It
+ * lets a single behavior declare a *heterogeneous* slot map where some
+ * slots are `Signal<T>` (writable) and others are `ReadonlySignal<T>`
+ * (read-only) — making read/write intent explicit at the call site and
+ * giving body-level enforcement (TS rejects `.set()` on a read-only slot).
+ */
+type AnySlotMap = Record<PropertyKey, ReadonlySignal<unknown>>;
+/**
+ * The deps object passed to each behavior by the composition.
+ *
+ * - `state` — slot map for state fields (reactive data). Per-slot read/
+ *   write intent expressed via `Signal<T>` vs `ReadonlySignal<T>`.
+ * - `context` — slot map for platform objects and actor references.
+ * - `config` — static configuration, passed once at composition creation.
+ */
+interface BehaviorDeps<StateMap extends AnySlotMap, ContextMap extends AnySlotMap, Cfg extends object> {
+  state: StateMap;
+  context: ContextMap;
+  config: Cfg;
+}
+/**
+ * A behavior announces the state and context keys it needs alongside a
+ * `setup` function that receives deps (state, context, config) and
+ * returns an optional cleanup handle.
+ *
+ * The `stateKeys` / `contextKeys` declarations are the runtime expression
+ * of the behavior's contract — the caller (e.g. `createComposition`) uses
+ * them to know which signals to provide. The setup parameter type
+ * declares the *slot map* (per-slot `Signal<T>` vs `ReadonlySignal<T>`);
+ * together they form a complete contract.
+ *
+ * Manual `Behavior<>` literals (e.g. engine wrappers that forward keys
+ * from a wrapped behavior, or pass-through behaviors like `shareSignals`)
+ * opt out of exhaustiveness — the type alias is permissive (subset).
+ * Source behaviors should use `defineBehavior` to get exhaustiveness
+ * enforcement at the call site.
+ */
+interface Behavior<StateMap extends AnySlotMap = Empty, ContextMap extends AnySlotMap = Empty, Cfg extends object = Empty> {
+  /** State keys this behavior reads/writes. Subset of `keyof StateMap`. */
+  stateKeys: readonly (keyof StateMap)[];
+  /** Context keys this behavior reads/writes. Subset of `keyof ContextMap`. */
+  contextKeys: readonly (keyof ContextMap)[];
+  setup: (deps: BehaviorDeps<StateMap, ContextMap, Cfg>) => BehaviorCleanup;
+}
+/** A behavior with an unconstrained setup — used as a generic bound. */
+type AnyBehavior = {
+  stateKeys: readonly PropertyKey[];
+  contextKeys: readonly PropertyKey[];
+  setup: (deps: any) => BehaviorCleanup;
+};
+/** Extract the deps type from a behavior's setup function. */
+type DepsOf<B> = B extends {
+  setup: (deps: infer D, ...args: any[]) => any;
+} ? D : never;
+/**
+ * Empty-object fallback used when a behavior omits state, context, or config.
+ *
+ * Using `{}` rather than `object` is deliberate — `object & {x: T}` collapses
+ * to `{x: never}` under TS's union-to-intersection conversion in some inference
+ * contexts (likely a TS quirk around the `object` upper bound), whereas
+ * `{} & {x: T}` simplifies cleanly to `{x: T}`.
+ */
+type Empty = {};
+/**
+ * Unwrap a signal map back to its state/context shape.
+ *
+ * Inferring through `{ get(): infer V }` rather than `Signal<infer V>`
+ * sidesteps `Signal`'s nominal/invariance behaviour — the conditional
+ * matches structurally on the read side, and `V` is inferred covariantly.
+ */
+type UnwrapSignals<M> = M extends object ? { [K in keyof M]: M[K] extends {
+  get(): infer V;
+} ? V : never; } : Empty;
+/** Infer the state shape a behavior requires from its deps parameter. */
+type InferBehaviorState<F> = DepsOf<F> extends {
+  state: infer M;
+} ? UnwrapSignals<M> : Empty;
+/** Infer the context shape a behavior requires from its deps parameter. */
+type InferBehaviorContext<F> = DepsOf<F> extends {
+  context: infer M;
+} ? UnwrapSignals<M> : Empty;
+/** Infer the config shape a behavior requires from its deps parameter. */
+type InferBehaviorConfig<F> = DepsOf<F> extends {
+  config: infer C extends object;
+} ? C : Empty;
+/**
+ * Recursively intersect a per-behavior projection across the tuple.
+ *
+ * Iterating over the tuple directly avoids `UnionToIntersection`'s
+ * function-contravariance trick, which produces unstable intersections
+ * (collapsing concrete fields to `never` or unrelated types) when one of the
+ * union members is the empty `{}` fallback.
+ */
+type IntersectBehaviors<Behaviors extends readonly AnyBehavior[], Project extends object> = Behaviors extends readonly [infer First extends AnyBehavior, ...infer Rest extends readonly AnyBehavior[]] ? Apply<Project, First> & IntersectBehaviors<Rest, Project> : Empty;
+/**
+ * Apply a projection (one of the marker types below) to a single behavior.
+ * Encoded as a discriminated dispatch so the recursion above can stay generic
+ * and we don't have to write three near-identical recursive types.
+ */
+type Apply<Project extends object, F> = Project extends {
+  kind: 'state';
+} ? InferBehaviorState<F> : Project extends {
+  kind: 'context';
+} ? InferBehaviorContext<F> : Project extends {
+  kind: 'config';
+} ? InferBehaviorConfig<F> : never;
+type StateProjection = {
+  kind: 'state';
+};
+type ContextProjection = {
+  kind: 'context';
+};
+type ConfigProjection = {
+  kind: 'config';
+};
+/** Resolve the combined state shape from an array of behaviors (intersection of all requirements). */
+type ResolveBehaviorState<Behaviors extends readonly AnyBehavior[]> = IntersectBehaviors<Behaviors, StateProjection> extends (infer R extends object) ? R : Empty;
+/** Resolve the combined context shape from an array of behaviors (intersection of all requirements). */
+type ResolveBehaviorContext<Behaviors extends readonly AnyBehavior[]> = IntersectBehaviors<Behaviors, ContextProjection> extends (infer R extends object) ? R : Empty;
+/** Resolve the combined config shape from an array of behaviors (intersection of all requirements). */
+type ResolveBehaviorConfig<Behaviors extends readonly AnyBehavior[]> = IntersectBehaviors<Behaviors, ConfigProjection> extends (infer R extends object) ? R : Empty;
+/**
+ * True if any property in `T` collapsed to `undefined` or `never` — indicating
+ * a type conflict from intersecting incompatible behavior requirements.
+ *
+ * - Required conflicts: `{ v: number } & { v: string }` → `{ v: never }` — caught via `[never] extends [undefined]`
+ * - Optional conflicts: `{ v?: number } & { v?: string }` → `{ v?: undefined }` — caught directly
+ */
+type HasConflict<T extends object> = true extends { [K in keyof T]: [T[K]] extends [undefined] ? true : never; }[keyof T] ? true : false;
+/**
+ * Validate that a behavior composition has no type conflicts.
+ * Returns the behaviors tuple if valid, or an error message type if conflicts are detected.
+ *
+ * State, context, and config are all checked the same way — by intersecting
+ * each behavior's requirement and looking for collapsed fields. The
+ * intersection-based check applies the same rule to context as to state, so
+ * two behaviors that disagree on a context field's type (e.g. `Surface` vs
+ * `VideoSurface`) surface a conflict at compose time. The prior subtype-based
+ * approach for owners is gone — the unified rule is simpler and catches the
+ * cases where two behaviors silently agreed on a wider supertype.
+ */
+type ValidateComposition<Behaviors extends readonly AnyBehavior[]> = HasConflict<ResolveBehaviorState<Behaviors>> extends true ? 'Error: behaviors have conflicting state types' : HasConflict<ResolveBehaviorContext<Behaviors>> extends true ? 'Error: behaviors have conflicting context types' : HasConflict<ResolveBehaviorConfig<Behaviors>> extends true ? 'Error: behaviors have conflicting config types' : [...Behaviors];
+/**
+ * A composition of behaviors with shared state and context signal maps.
+ */
+interface Composition<S extends object, C extends object> {
+  state: StateSignals<S>;
+  context: ContextSignals<C>;
+  destroy(): Promise<void>;
+}
+/**
+ * Options for `createComposition`.
+ *
+ * Composition derives the state and context signal maps from each
+ * behavior's declared `stateKeys` / `contextKeys`; `initialState` and
+ * `initialContext` seed those signals at creation time. Any unseeded
+ * signal starts as `undefined`.
+ */
+interface CompositionOptions<S extends object, C extends object, Cfg extends object> {
+  /** Static configuration passed to every behavior. */
+  config?: Cfg;
+  /** Initial values for state signals — any subset of `keyof S`. */
+  initialState?: Partial<S>;
+  /** Initial values for context signals — any subset of `keyof C`. */
+  initialContext?: Partial<C>;
+}
+declare function createComposition<const Behaviors extends readonly AnyBehavior[]>(behaviors: ValidateComposition<Behaviors>, options?: CompositionOptions<ResolveBehaviorState<Behaviors>, ResolveBehaviorContext<Behaviors>, ResolveBehaviorConfig<Behaviors>>): Composition<ResolveBehaviorState<Behaviors>, ResolveBehaviorContext<Behaviors>>;
+/**
+ * Compose-time exhaustiveness check.
+ *
+ * Adds a phantom error tag to the parameter shape when `Keys` does not
+ * cover every key in `Slot`. The user's value won't satisfy the phantom
+ * field requirement, so TS surfaces the failure at the call site with a
+ * descriptive message. When exhaustive, the tag is `Empty` and adds no
+ * constraint.
+ */
+type ExhaustiveKeys<Keys extends readonly PropertyKey[], Slot extends object, Name extends string> = [keyof Slot] extends [Keys[number]] ? Empty : { [K in `Error: ${Name}Keys must list every key in the typed slice`]: Exclude<keyof Slot, Keys[number]>; };
+/**
+ * Typed factory for behaviors that enforces single-behavior key/param
+ * consistency: declared `stateKeys` must equal `keyof S` (where `S` is
+ * inferred from the setup's `state` parameter type), and same for
+ * `contextKeys` / `C`.
+ *
+ * The `const` modifier on `SK` / `CK` captures literal tuples so e.g.
+ * `stateKeys: ['preload']` infers as `readonly ['preload']`, no `as
+ * const` needed at the call site.
+ *
+ * Cross-behavior consistency at `createComposition` is unchanged — the
+ * existing `IntersectBehaviors` machinery still runs over each
+ * behavior's setup param type.
+ *
+ * @example
+ * ```ts
+ * export const syncPreload = defineBehavior({
+ *   stateKeys: ['preload'],
+ *   contextKeys: ['mediaElement'],
+ *   setup: ({ state, context }: {
+ *     state: StateSignals<{ preload?: 'auto' | 'metadata' | 'none' }>;
+ *     context: ContextSignals<{ mediaElement?: HTMLMediaElement | undefined }>;
+ *   }) => { ... },
+ * });
+ * ```
+ */
+/**
+ * Deps shape for a behavior whose deps slot is empty (no keys). When a
+ * slot is empty, the corresponding deps field is optional — callers
+ * (typically tests) can omit it, and it defaults to `{}` at runtime via
+ * `createComposition`.
+ *
+ * When a slot has at least one key, the behavior reads `state.foo` /
+ * `context.bar` / `config.baz` and we need the field to be required so
+ * the access is type-safe.
+ */
+type RequireIfNonEmpty<Key extends string, T extends object> = keyof T extends never ? { [K in Key]?: T; } : { [K in Key]: T; };
+type DepsForCfg<StateMap extends AnySlotMap, ContextMap extends AnySlotMap, Cfg extends object> = RequireIfNonEmpty<'state', StateMap> & RequireIfNonEmpty<'context', ContextMap> & RequireIfNonEmpty<'config', Cfg>;
+declare function defineBehavior<StateMap extends AnySlotMap = Empty, ContextMap extends AnySlotMap = Empty, Cfg extends object = Empty, const SK extends readonly (keyof StateMap)[] = readonly [], const CK extends readonly (keyof ContextMap)[] = readonly [], R extends BehaviorCleanup = BehaviorCleanup>(behavior: {
+  stateKeys: SK;
+  contextKeys: CK;
+  setup: (deps: {
+    state: StateMap;
+    context: ContextMap;
+    config: Cfg;
+  }) => R;
+} & ExhaustiveKeys<SK, StateMap, 'state'> & ExhaustiveKeys<CK, ContextMap, 'context'>): {
+  stateKeys: SK;
+  contextKeys: CK;
+  setup: (deps: DepsForCfg<StateMap, ContextMap, Cfg>) => R;
+};
+//#endregion
+export { AnySlotMap, Behavior, BehaviorCleanup, BehaviorDeps, Composition, CompositionOptions, ContextSignals, InferBehaviorConfig, InferBehaviorContext, InferBehaviorState, ResolveBehaviorConfig, ResolveBehaviorContext, ResolveBehaviorState, StateSignals, createComposition, defineBehavior };
+//# sourceMappingURL=create-composition.d.ts.map