@preact/signals-core/dist/signals-core.d.ts

Manage state with style in every framework

declare const BRAND_SYMBOL: unique symbol;
type Node = {
    _source: Signal;
    _prevSource?: Node;
    _nextSource?: Node;
    _target: Computed | Effect;
    _prevTarget?: Node;
    _nextTarget?: Node;
    _version: number;
    _rollbackNode?: Node;
};
/**
 * Combine multiple value updates into one "commit" at the end of the provided callback.
 *
 * Batches can be nested and changes are only flushed once the outermost batch callback
 * completes.
 *
 * Accessing a signal that has been modified within a batch will reflect its updated
 * value.
 *
 * @param fn The callback function.
 * @returns The value returned by the callback.
 */
declare function batch<T>(fn: () => T): T;
/**
 * Run a callback function that can access signal values without
 * subscribing to the signal updates.
 *
 * @param fn The callback function.
 * @returns The value returned by the callback.
 */
declare function untracked<T>(fn: () => T): T;
/**
 * The base class for plain and computed signals.
 */
declare class Signal<T = any> {
    constructor(value?: T, options?: SignalOptions<T>);
    subscribe(fn: (value: T) => void): () => void;
    name?: string;
    valueOf(): T;
    toString(): string;
    toJSON(): T;
    peek(): T;
    brand: typeof BRAND_SYMBOL;
    get value(): T;
    set value(value: T);
}
export interface SignalOptions<T = any> {
    watched?: (this: Signal<T>) => void;
    unwatched?: (this: Signal<T>) => void;
    name?: string;
}
/**
 * Create a new plain signal.
 *
 * @param value The initial value for the signal.
 * @returns A new signal.
 */
export declare function signal<T>(value: T, options?: SignalOptions<T>): Signal<T>;
export declare function signal<T = undefined>(): Signal<T | undefined>;
/**
 * The base class for computed signals.
 */
declare class Computed<T = any> extends Signal<T> {
    _fn: () => T;
    _sources?: Node;
    _globalVersion: number;
    _flags: number;
    constructor(fn: () => T, options?: SignalOptions<T>);
    _notify(): void;
    get value(): T;
}
/**
 * An interface for read-only signals.
 */
interface ReadonlySignal<T = any> {
    readonly value: T;
    peek(): T;
    subscribe(fn: (value: T) => void): () => void;
    valueOf(): T;
    toString(): string;
    toJSON(): T;
    brand: typeof BRAND_SYMBOL;
}
/**
 * Create a new signal that is computed based on the values of other signals.
 *
 * The returned computed signal is read-only, and its value is automatically
 * updated when any signals accessed from within the callback function change.
 *
 * @param fn The effect callback.
 * @returns A new read-only signal.
 */
declare function computed<T>(fn: () => T, options?: SignalOptions<T>): ReadonlySignal<T>;
type EffectFn = ((this: {
    dispose: () => void;
}) => void | (() => void)) | (() => void | (() => void));
type DisposeSymbol = typeof Symbol extends {
    readonly dispose: infer TDispose;
} ? TDispose : never;
type DisposableLike = {
    [K in DisposeSymbol & PropertyKey]: () => void;
};
type DisposeFn = (() => void) & DisposableLike;
/**
 * The base class for reactive effects.
 */
declare class Effect {
    _fn?: EffectFn;
    _cleanup?: () => void;
    _sources?: Node;
    _nextBatchedEffect?: Effect;
    _flags: number;
    _debugCallback?: () => void;
    name?: string;
    constructor(fn: EffectFn, options?: EffectOptions);
    _callback(): void;
    _start(): () => void;
    _notify(): void;
    _dispose(): void;
    dispose(): void;
}
export interface EffectOptions {
    name?: string;
}
/**
 * Create an effect to run arbitrary code in response to signal changes.
 *
 * An effect tracks which signals are accessed within the given callback
 * function `fn`, and re-runs the callback when those signals change.
 *
 * The callback may return a cleanup function. The cleanup function gets
 * run once, either when the callback is next called or when the effect
 * gets disposed, whichever happens first.
 *
 * @param fn The effect callback.
 * @returns A function for disposing the effect.
 */
declare function effect(fn: EffectFn, options?: EffectOptions): DisposeFn;
declare function action<TArgs extends unknown[], TReturn>(fn: (...args: TArgs) => TReturn): (...args: TArgs) => TReturn;
/** Models should only contain signals, actions, and nested objects containing only signals and actions. */
type ValidateModel<TModel> = {
    [Key in keyof TModel]: TModel[Key] extends ReadonlySignal<unknown> ? TModel[Key] : TModel[Key] extends (...args: any[]) => any ? TModel[Key] : TModel[Key] extends object ? ValidateModel<TModel[Key]> : `Property ${Key extends string ? `'${Key}' ` : ""}is not a Signal, Action, or an object that contains only Signals and Actions.`;
};
export type Model<TModel> = ValidateModel<TModel> & DisposableLike;
export type ModelFactory<TModel, TFactoryArgs extends any[] = []> = (...args: TFactoryArgs) => ValidateModel<TModel>;
export type ModelConstructor<TModel, TFactoryArgs extends any[] = []> = new (...args: TFactoryArgs) => Model<TModel>;
declare function createModel<TModel, TFactoryArgs extends any[] = []>(modelFactory: ModelFactory<TModel, TFactoryArgs>): ModelConstructor<TModel, TFactoryArgs>;
export { computed, effect, batch, untracked, action, createModel, Signal, ReadonlySignal, Effect, Computed, };