import { Optional } from './common';
export declare const head: <T>(array: T[]) => Optional<T>;
export declare const last: <T>(array: T[]) => Optional<T>;
export declare const tail: <T>(array?: T[]) => T[];
export declare const isArray: <T>(array: T | T[]) => array is T[];
export declare const cutHead: <T>([head, ...tail]: T[]) => {
    head: T;
    tail: T[];
};
export declare const length: <T>(arr: T[]) => number;
export declare const isEmpty: <T>(array: T[]) => boolean;
export declare const toArray: <T>(value: T | T[]) => T[];
export declare type Remove = {
    <T>(remove: T, from: T[]): T[];
    <T>(remove: T): (from: T[]) => T[];
};
export declare const remove: Remove;
export declare type Concat = {
    <A, B>(a: A, b: B): A;
    <A, B>(a: A): (b: B) => A;
};
export declare const concat: Concat;
export declare const prepend: <T>(value: any, array: T[]) => T[];
export declare type Find = {
    <T>(func: (bit: T) => boolean, array: T[]): Optional<T>;
    <T>(func: (bit: T) => boolean): (array: T[]) => Optional<T>;
};
export declare const find: Find;
export declare type Filter = {
    <T>(func: (a: T, index: number) => boolean, over: T[]): T[];
    <T>(func: (a: T, index: number) => boolean): (over: T[]) => T[];
};
export declare const filter: Filter;
export declare type Map = {
    <T, R>(func: (a: T, index: number) => R, over: T[]): R[];
    <T, R>(func: (a: T, index: number) => R): (over: T[]) => R[];
};
export declare const map: Map;