import { Observable } from "rxjs";
/**
 * Wraps an Observable in a Proxy that enables property chaining.
 * When accessing a property ending with `$`, it uses switchMap to chain
 * to that property's observable value.
 * When accessing a non-observable property, it returns an Observable of that property's value.
 */
export declare function chainable<T>(observable: Observable<T>): ChainableObservable<T>;
/**
 * Helper type to extract nullable parts (undefined/null) from a type
 */
type NullableParts<T> = Extract<T, undefined | null>;
/**
 * Helper type to get the property type, preserving nullable parts from the parent type
 */
type PropChain<T, K extends keyof NonNullable<T>> = NonNullable<T>[K] | NullableParts<T>;
/**
 * A chainable Observable type that allows property chaining.
 * This type maps all properties to chainable observables:
 * - Properties ending with $: extracts inner type from Observable<U> → ChainableObservable<U>
 * - Other properties: uses property type directly → ChainableObservable<PropertyType>
 *
 * Note: TypeScript has limitations inferring through Proxy types. For better
 * type inference, you may need to explicitly type the result:
 */
export type ChainableObservable<T> = Observable<T> & Omit<{
    [K in keyof NonNullable<T> as K extends string ? K : never]: K extends `${infer _}$` ? NonNullable<T>[K] extends Observable<infer U> ? ChainableObservable<U | NullableParts<T>> : never : ChainableObservable<PropChain<T, K>>;
}, "$first" | "$last"> & {
    /** Returns a promise that resolves with the first value or rejects with a timeout error */
    $first(first?: number): Promise<NonNullable<T>>;
    $first<V>(first?: number, fallback?: V): Promise<NonNullable<T> | V>;
    /** Returns a promise that resolves with the last value or rejects with a timeout error */
    $last(max?: number): Promise<NonNullable<T>>;
    $last<V>(max?: number, fallback?: V): Promise<NonNullable<T> | V>;
};
export {};