/** A generic subscriber that takes a value emitted by a signal as its only parameter. */
export declare type Subscriber<T> = (current: T) => void;
/** A function that's used to unsubscribe a subscriber from a signal. */
export declare type Unsubscribe = () => void;
/** A signal that can have subscribers and emit values to them. */
export declare type ReadonlySignal<T> = {
    /**
     * Subscribe a function to this signal.
     *
     * Note: subscribers are deduplicated, if you need to subscribe the same
     * function more than once wrap it in an arrow function, e.g.
     * `signal$.subscribe((v) => myFunc(v));`
     * @param subscriber a function that will be called when this signal emits.
     */
    subscribe(subscriber: Subscriber<T>): Unsubscribe;
    /**
     * Subscribe a function to this signal and automatically unsubscribe it after one emit occurs.
     *
     * @param subscriber a function that will be called when this signal emits.
     */
    subscribeOnce(subscriber: Subscriber<T>): Unsubscribe;
    /**
     * Return the current number of active subscriptions.
     */
    nOfSubscriptions(): number;
};
/** A signal that can have subscribers and emit values to them. */
export declare type Signal<T> = ReadonlySignal<T> & {
    /**
     * Emit a value to all subscribers.
     * @param v the value to emit.
     */
    emit(v: T): void;
};
/**
 * Make a signal of type T.
 *
 * Example usage:
 * ```ts
 * const signal$ = makeSignal<number>();
 * signal$.emit(10);
 * ```
 * Example usage with no data:
 * ```ts
 * const signal$ = makeSignal<void>();
 * signal$.emit();
 * ```
 * @returns a signal.
 */
export declare function makeSignal<T>(): Signal<T>;
export * from './composition';