import { OmitType, ValueOf } from '../types';
import { KeysRecursive, PrimitiveRecursive } from './recursive.type';
export declare type ObjectFilter<O> = (k: keyof O, v: ValueOf<O>) => boolean;
export declare const filter: <O extends {}>(o: O, filter: ObjectFilter<O>) => O;
export declare const removeUndefined: <O extends {}>(o: O) => OmitType<O, undefined>;
export declare const getIfDefined: <T extends {} | any[] | readonly any[], K extends keyof T>(o: T, key: K, defaultValue?: T[K]) => T[K];
export interface ReduceOptions<R> {
    init: R;
    isRecursive?: boolean;
}
export declare type ReduceReducer<T, R> = (current: R, key: KeysRecursive<T>, v: PrimitiveRecursive<T>) => R;
export declare const reduce: <T extends {} | any[] | readonly any[], R>(o: T, reducer: ReduceReducer<T, R>, initOrOptions: R | ReduceOptions<R>) => R;