import { Observable, OperatorFunction } from "rxjs";
export declare function isNotNullish<T>(): (source$: Observable<null | undefined | T>) => Observable<T>;
export declare function isNotNull<T>(): (source$: Observable<null | undefined | T>) => Observable<T | undefined>;
export declare function isNotUndefined<T>(): (source$: Observable<null | undefined | T>) => Observable<T | null>;
export declare function watchList<T, R>(select: (item: T) => Observable<R>): OperatorFunction<T[], T[]>;
export declare function mergeWatchList<T, S>(predicate: (item: T) => Observable<S[]>): OperatorFunction<T[], S[]>;
export declare function mergeWatchIndex<T, S>(predicate: (item: T) => Observable<{
    [pointer: string]: S;
}>): OperatorFunction<T[], {
    [pointer: string]: S;
}>;
export declare function toIndex<T>(getIndex: (item: T) => string): OperatorFunction<T[], {
    [pointer: string]: T;
}>;
export declare function makeIndex<T>(itemList: T[], getIndex: (item: T) => string): {
    [pointer: string]: T;
};
export declare function mergeIndex<T>(indexes: {
    [pointer: string]: T;
}[]): {
    [pointer: string]: T;
};
export declare function mandatoryPluckSwitchMap<T, R, K extends keyof T>(attr: K, project: (v: T[K]) => Observable<R> | null | undefined, distinct?: boolean): OperatorFunction<T, R>;
export declare function optionalPluckSwitchMap<T, R, K extends keyof T>(attr: K, project: (v: T[K] | null | undefined) => Observable<R> | null | undefined, distinct?: boolean): OperatorFunction<T | undefined, R | undefined>;
export declare function mandatorySwitchMap<T, R>(project: (v: T) => Observable<R> | null | undefined): OperatorFunction<T, R>;
export declare function optionalSwitchMap<T, R>(project: (v: T | null | undefined) => Observable<R> | null | undefined): OperatorFunction<T | undefined, R | undefined>;
export declare function mandatoryPluck<T, K extends keyof T>(attr: K): OperatorFunction<T, T[K]>;
export declare function optionalPluck<T, K extends keyof T>(attr: K): OperatorFunction<T | undefined, T[K] | undefined>;
export declare function mandatory<T, R extends T>(): OperatorFunction<T | null | undefined, R>;
export declare function flattenAndRemoveNullish<T, R extends NonNullable<T>>(): OperatorFunction<T[][], R[]>;
export declare function removeNullish<T, R extends NonNullable<T>>(): OperatorFunction<T[], R[]>;