@types/ramda/index.d.ts

// Type definitions for ramda 0.28
// Project: https://ramdajs.com
// Definitions by: Scott O'Malley <https://github.com/TheHandsomeCoder>
//                 Erwin Poeze <https://github.com/donnut>
//                 Matt DeKrey <https://github.com/mdekrey>
//                 Stephen King <https://github.com/sbking>
//                 Alejandro Fernandez Haro <https://github.com/afharo>
//                 Vítor Castro <https://github.com/teves-castro>
//                 Simon Højberg <https://github.com/hojberg>
//                 Samson Keung <https://github.com/samsonkeung>
//                 Angelo Ocana <https://github.com/angeloocana>
//                 Rayner Pupo <https://github.com/raynerd>
//                 Nikita Moshensky <https://github.com/moshensky>
//                 Ethan Resnick <https://github.com/ethanresnick>
//                 Tomas Szabo <https://github.com/deftomat>
//                 Maciek Blim <https://github.com/blimusiek>
//                 Marcin Biernat <https://github.com/biern>
//                 Rayhaneh Banyassady <https://github.com/rayhaneh>
//                 Ryan McCuaig <https://github.com/rgm>
//                 John Ottenlips <https://github.com/jottenlips>
//                 Nitesh Phadatare <https://github.com/minitesh>
//                 Krantisinh Deshmukh <https://github.com/krantisinh>
//                 Aram Kharazyan <https://github.com/nemo108>
//                 Jituan Lin <https://github.com/jituanlin>
//                 Philippe Mills <https://github.com/Philippe-mills>
//                 Saul Mirone <https://github.com/Saul-Mirone>
//                 Nicholai Nissen <https://github.com/Nicholaiii>
//                 Jorge Santana <https://github.com/LORDBABUINO>
//                 Mikael Couzic <https://github.com/couzic>
//                 Nikita Balikhin <https://github.com/NEWESTERS>
//                 Wang Zengdi <https://github.com/adispring>
//                 Marcus Blättermann <https://github.com/essenmitsosse>
// Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
// TypeScript Version: 4.2

import * as _ from 'ts-toolbelt';
import {
    AnyConstructor,
    AnyFunction,
    AtLeastOneFunctionsFlow,
    AtLeastOneFunctionsFlowFromRightToLeft,
    AssocPartialOne,
    CondPair,
    CondPairTypeguard,
    Dictionary,
    Evolvable,
    Evolve,
    Evolver,
    Falsy,
    Find,
    Functor,
    InputTypesOfFns,
    KeyValuePair,
    Lens,
    Merge,
    MergeAll,
    ObjectHavingSome,
    ObjPred,
    Ord,
    Ordering,
    Path,
    Placeholder,
    Pred,
    PredTypeguard,
    Reduced,
    ReturnTypesOfFns,
    ValueOfUnion,
    Take,
    ToTupleOfArray,
    ToTupleOfFunction,
    Tuple,
    Fn,
    IfFunctionsArgumentsDoNotOverlap,
    LargestArgumentsList,
    mergeArrWithLeft,
    Prop,
} from './tools';

export * from './tools';

// NOTE: Example doesn't work with current level of support
/**
 * A special placeholder value used to specify "gaps" within curried functions,
 * allowing partial application of any combination of arguments, regardless of their positions.
 *
 * If `g` is a curried ternary function and `_` is `R.__`, the following are equivalent:
 *  - `g(1, 2, 3)`
 *  - `g(_, 2, 3)(1)`
 *  - `g(_, _, 3)(1)(2)`
 *  - `g(_, _, 3)(1, 2)`
 *  - `g(_, 2, _)(1, 3)`
 *  - `g(_, 2)(1)(3)`
 *  - `g(_, 2)(1, 3)`
 *  - `g(_, 2)(_, 3)(1)`
 *
 * @example
 * ```typescript
 * const greet = R.replace('{name}', R.__, 'Hello, {name}!');
 * greet('Alice'); //=> 'Hello, Alice!'
 * ```
 */
export const __: Placeholder;

/**
 * Adds two values. Equivalent to `a + b` but curried.
 *
 * @example
 * ```typescript
 * R.add(2, 3);       //=>  5
 * R.add(7)(10);      //=> 17
 * ```
 */
export function add(a: number, b: number): number;
export function add(a: number): (b: number) => number;

/**
 * Creates a new list iteration function from an existing one by adding two new parameters to its callback
 * function: the current index, and the entire list.
 *
 * This would turn, for instance, {@link map `R.map`} function into one that more closely resembles `Array.prototype.map`.
 *
 * @note This will only work for functions in which the iteration callback function is the first parameter,
 * and where the list is the last parameter.
 * (This latter might be unimportant if the list parameter is not used.)
 *
 * See also {@link subtract}.
 *
 * @example
 * ```typescript
 * const mapIndexed = R.addIndex(R.map);
 * mapIndexed((val, idx) => idx + '-' + val, ['f', 'o', 'o', 'b', 'a', 'r']);
 * //=> ['0-f', '1-o', '2-o', '3-b', '4-a', '5-r']
 * ```
 */
/* Special case for forEach */
export function addIndex<T>(
    fn: (f: (item: T) => void, list: readonly T[]) => T[],
): _.F.Curry<(a: (item: T, idx: number, list: T[]) => void, b: readonly T[]) => T[]>;
/* Special case for filter */
export function addIndex<T>(
    fn: (f: (item: T) => boolean, list: readonly T[]) => T[],
): _.F.Curry<(a: (item: T, idx: number, list: T[]) => boolean, b: readonly T[]) => T[]>;
/* Special case for map */
export function addIndex<T, U>(
    fn: (f: (item: T) => U, list: readonly T[]) => U[],
): _.F.Curry<(a: (item: T, idx: number, list: T[]) => U, b: readonly T[]) => U[]>;
/* Special case for reduce */
export function addIndex<T, U>(
    fn: (f: (acc: U, item: T) => U, aci: U, list: readonly T[]) => U,
): _.F.Curry<(a: (acc: U, item: T, idx: number, list: T[]) => U, b: U, c: readonly T[]) => U>;

/**
 * Applies a function to the value at the given index of an array, returning a new copy of the array with the
 * element at the given index replaced with the result of the function application.
 *
 * See also {@link update}.
 *
 * @example
 * ```typescript
 * R.adjust(1, R.toUpper, ['a', 'b', 'c', 'd']);      //=> ['a', 'B', 'c', 'd']
 * R.adjust(-1, R.toUpper, ['a', 'b', 'c', 'd']);     //=> ['a', 'b', 'c', 'D']
 * ```
 */
export function adjust<T>(index: number, fn: (a: T) => T, list: readonly T[]): T[];
export function adjust<T>(index: number, fn: (a: T) => T): (list: readonly T[]) => T[];

/**
 * Returns `true` if all elements of the list match the predicate, `false` if there are any that don't.
 *
 * Dispatches to the `all` method of the second argument, if present.
 *
 * Acts as a transducer if a transformer is given in list position.
 *
 * See also {@link any}, {@link none}, {@link transduce}.
 *
 * @example
 * ```typescript
 * const equals3 = R.equals(3);
 * R.all(equals3)([3, 3, 3, 3]); //=> true
 * R.all(equals3)([3, 3, 1, 3]); //=> false
 * ```
 */
export function all<T>(fn: (a: T) => boolean, list: readonly T[]): boolean;
export function all<T>(fn: (a: T) => boolean): (list: readonly T[]) => boolean;

/**
 * Takes a list of predicates and returns a predicate that returns true for a given list of arguments
 * if every one of the provided predicates is satisfied by those arguments.
 *
 * The function returned is a curried function whose arity matches that of the highest-arity predicate.
 *
 * See also {@link anyPass}.
 *
 * @example
 * ```typescript
 * type Card = { rank: string; suit: string; };
 *
 * const isQueen = R.propEq('rank', 'Q');
 * const isSpade = R.propEq('suit', '♠︎');
 * const isQueenOfSpades = R.allPass<R.Pred<[Card]>>([isQueen, isSpade]);
 *
 * isQueenOfSpades({rank: 'Q', suit: '♣︎'}); //=> false
 * isQueenOfSpades({rank: 'Q', suit: '♠︎'}); //=> true
 * ```
 */
export function allPass<T, TF1 extends T, TF2 extends T>(
    preds: [PredTypeguard<T, TF1>, PredTypeguard<T, TF2>],
): (a: T) => a is TF1 & TF2;
export function allPass<T, TF1 extends T, TF2 extends T, TF3 extends T>(
    preds: [PredTypeguard<T, TF1>, PredTypeguard<T, TF2>, PredTypeguard<T, TF3>],
): (a: T) => a is TF1 & TF2 & TF3;
export function allPass<T, TF1 extends T, TF2 extends T, TF3 extends T>(
    preds: [PredTypeguard<T, TF1>, PredTypeguard<T, TF2>, PredTypeguard<T, TF3>],
): (a: T) => a is TF1 & TF2 & TF3;
export function allPass<T, TF1 extends T, TF2 extends T, TF3 extends T, TF4 extends T>(
    preds: [PredTypeguard<T, TF1>, PredTypeguard<T, TF2>, PredTypeguard<T, TF3>, PredTypeguard<T, TF4>],
): (a: T) => a is TF1 & TF2 & TF3 & TF4;
export function allPass<T, TF1 extends T, TF2 extends T, TF3 extends T, TF4 extends T, TF5 extends T>(
    preds: [
        PredTypeguard<T, TF1>,
        PredTypeguard<T, TF2>,
        PredTypeguard<T, TF3>,
        PredTypeguard<T, TF4>,
        PredTypeguard<T, TF5>,
    ],
): PredTypeguard<T, TF1 & TF2 & TF3 & TF4 & TF5>;
export function allPass<T, TF1 extends T, TF2 extends T, TF3 extends T, TF4 extends T, TF5 extends T, TF6 extends T>(
    preds: [
        PredTypeguard<T, TF1>,
        PredTypeguard<T, TF2>,
        PredTypeguard<T, TF3>,
        PredTypeguard<T, TF4>,
        PredTypeguard<T, TF5>,
        PredTypeguard<T, TF6>,
    ],
): PredTypeguard<T, TF1 & TF2 & TF3 & TF4 & TF5 & TF6>;
export function allPass<F extends Pred>(preds: readonly F[]): F;

/**
 * Returns a function that always returns the given value.
 *
 * @note For non-primitives the value returned is a reference to the original value.
 *
 * This function is known as `const`, `constant`, or `K` (for K combinator) in other languages and libraries.
 *
 * @example
 * ```typescript
 * const t = R.always('Tee');
 * t(); //=> 'Tee'
 * ```
 */
export function always<T>(val: T): (...args: unknown[]) => T;

/**
 * A function that returns the first argument if it's falsy otherwise the second argument.
 *
 * See also {@link both}, {@link or}, {@link xor}.
 *
 * @note This is **not** short-circuited, meaning that if expressions are passed they are both evaluated.
 *
 * @example
 * ```typescript
 * R.and(true, true); //=> true
 * R.and(true, false); //=> false
 * R.and(false, true); //=> false
 * R.and(false, false); //=> false
 * ```
 */
export function and<T, U>(a: T, b: U): T | U;
export function and<T>(a: T): <U>(b: U) => T | U;

/**
 * Returns the result of applying the `onSuccess` function to the value inside a successfully resolved `Promise`.
 * This is useful for working with `Promise`s inside function compositions.
 *
 * See also {@link otherwise}.
 *
 * @example
 * ```typescript
 * type Query = { query: { email: string; }; };
 *
 * const makeQuery = (email: string) => ({ query: { email }});
 * const fetchMember = (request: Query) =>
 *   Promise.resolve({ firstName: 'Bob', lastName: 'Loblaw', id: 42 });
 *
 * //getMemberName :: String -> Promise ({ firstName, lastName })
 * const getMemberName = R.pipe(
 *   makeQuery,
 *   fetchMember,
 *   R.andThen(R.pick(['firstName', 'lastName']))
 * );
 *
 * getMemberName('bob@gmail.com').then(console.log);
 * ```
 */
export function andThen<A, B>(onSuccess: (a: A) => B | Promise<B>, promise: Promise<A>): Promise<B>;
export function andThen<A, B>(onSuccess: (a: A) => B | Promise<B>): (promise: Promise<A>) => Promise<B>;

/**
 * Returns `true` if at least one of elements of the list match the predicate, `false` otherwise.
 *
 * Dispatches to the `any` method of the second argument, if present.
 *
 * Acts as a transducer if a transformer is given in list position.
 *
 * See also {@link all}, {@link none}, {@link transduce}.
 *
 * @example
 * ```typescript
 * const lessThan0 = R.flip(R.lt)(0);
 * const lessThan2 = R.flip(R.lt)(2);
 * R.any(lessThan0)([1, 2]); //=> false
 * R.any(lessThan2)([1, 2]); //=> true
 * ```
 */
export function any<T>(fn: (a: T) => boolean, list: readonly T[]): boolean;
export function any<T>(fn: (a: T) => boolean): (list: readonly T[]) => boolean;

/**
 * Takes a list of predicates and returns a predicate that returns true for a
 * given list of arguments if at least one of the provided predicates is
 * satisfied by those arguments.
 *
 * The function returned is a curried function whose arity matches that of the
 * highest-arity predicate.
 *
 * See also {@link allPass}.
 *
 * @example
 * ```typescript
 * type Card = { rank: string; suit: string; };
 *
 * const isClub = R.propEq('suit', '♣');
 * const isSpade = R.propEq('suit', '♠');
 * const isBlackCard = R.anyPass<R.Pred<[Card]>>([isClub, isSpade]);
 *
 * isBlackCard({rank: '10', suit: '♣'}); //=> true
 * isBlackCard({rank: 'Q', suit: '♠'}); //=> true
 * isBlackCard({rank: 'Q', suit: '♦'}); //=> false
 * ```
 */
export function anyPass<T, TF1 extends T, TF2 extends T>(
    preds: [PredTypeguard<T, TF1>, PredTypeguard<T, TF2>],
): (a: T) => a is TF1 | TF2;
export function anyPass<T, TF1 extends T, TF2 extends T, TF3 extends T>(
    preds: [PredTypeguard<T, TF1>, PredTypeguard<T, TF2>, PredTypeguard<T, TF3>],
): (a: T) => a is TF1 | TF2 | TF3;
export function anyPass<T, TF1 extends T, TF2 extends T, TF3 extends T>(
    preds: [PredTypeguard<T, TF1>, PredTypeguard<T, TF2>, PredTypeguard<T, TF3>],
): (a: T) => a is TF1 | TF2 | TF3;
export function anyPass<T, TF1 extends T, TF2 extends T, TF3 extends T, TF4 extends T>(
    preds: [PredTypeguard<T, TF1>, PredTypeguard<T, TF2>, PredTypeguard<T, TF3>, PredTypeguard<T, TF4>],
): (a: T) => a is TF1 | TF2 | TF3 | TF4;
export function anyPass<T, TF1 extends T, TF2 extends T, TF3 extends T, TF4 extends T, TF5 extends T>(
    preds: [
        PredTypeguard<T, TF1>,
        PredTypeguard<T, TF2>,
        PredTypeguard<T, TF3>,
        PredTypeguard<T, TF4>,
        PredTypeguard<T, TF5>,
    ],
): PredTypeguard<T, TF1 | TF2 | TF3 | TF4 | TF5>;
export function anyPass<T, TF1 extends T, TF2 extends T, TF3 extends T, TF4 extends T, TF5 extends T, TF6 extends T>(
    preds: [
        PredTypeguard<T, TF1>,
        PredTypeguard<T, TF2>,
        PredTypeguard<T, TF3>,
        PredTypeguard<T, TF4>,
        PredTypeguard<T, TF5>,
        PredTypeguard<T, TF6>,
    ],
): PredTypeguard<T, TF1 | TF2 | TF3 | TF4 | TF5 | TF6>;
export function anyPass<F extends Pred>(preds: readonly F[]): F;

/**
 * `ap` applies a list of functions to a list of values.
 *
 * Dispatches to the `ap` method of the first argument, if present.
 * Also treats curried functions as applicatives.
 *
 * @example
 * ```typescript
 * R.ap([R.multiply(2), R.add(3)], [1,2,3]); //=> [2, 4, 6, 4, 5, 6]
 * R.ap([R.concat('tasty '), R.toUpper], ['pizza', 'salad']); //=> ["tasty pizza", "tasty salad", "PIZZA", "SALAD"]
 *
 * // R.ap can also be used as S combinator
 * // when only two functions are passed
 * R.ap((s, s2) => R.concat(s, s2), R.toUpper)('Ramda') //=> 'RamdaRAMDA'
 * ```
 */
export function ap<T, U>(fns: ReadonlyArray<(a: T) => U>, vs: readonly T[]): U[];
export function ap<T, U>(fns: ReadonlyArray<(a: T) => U>): (vs: readonly T[]) => U[];
export function ap<R, A, B>(fn: (r: R, a: A) => B, fn1: (r: R) => A): (r: R) => B;

/**
 * Returns a new list, composed of n-tuples of consecutive elements.
 * If `n` is greater than the length of the list, an empty list is returned.
 *
 * Acts as a transducer if a transformer is given in list position.
 *
 * See also {@link transduce}.
 *
 * @example
 * ```typescript
 * R.aperture(2, [1, 2, 3, 4, 5]); //=> [[1, 2], [2, 3], [3, 4], [4, 5]]
 * R.aperture(3, [1, 2, 3, 4, 5]); //=> [[1, 2, 3], [2, 3, 4], [3, 4, 5]]
 * R.aperture(7, [1, 2, 3, 4, 5]); //=> []
 * ```
 */
export function aperture<N extends number, T>(n: N, list: readonly T[]): Array<Tuple<T, N>> | [];
export function aperture<N extends number>(n: N): <T>(list: readonly T[]) => Array<Tuple<T, N>> | [];

/**
 * Returns a new list containing the contents of the given list, followed by the given element.
 *
 * See also {@link prepend}.
 *
 * @example
 * ```typescript
 * R.append('tests', ['write', 'more']); //=> ['write', 'more', 'tests']
 * R.append('tests', []); //=> ['tests']
 * R.append<string | string[]>(['tests'], ['write', 'more']); //=> ['write', 'more', ['tests']]
 * ```
 */
export function append<T>(el: T, list: readonly T[]): T[];
export function append<T>(el: T): (list: readonly T[]) => T[];

/**
 * Applies function `fn` to the argument list `args`.
 * This is useful for creating a fixed-arity function from a variadic function.
 * `fn` should be a bound function if context is significant.
 *
 * See also {@link call}, {@link unapply}.
 */
export function apply<F extends AnyFunction>(fn: F, args: Parameters<F>): ReturnType<F>;
export function apply<F extends AnyFunction>(fn: F): (args: Parameters<F>) => ReturnType<F>;

/**
 * Given a spec object recursively mapping properties to functions,
 * creates a function producing an object of the same structure,
 * by mapping each property to the result of calling its associated function with the supplied arguments.
 *
 * See also {@link converge}, {@link juxt}.
 *
 * @example
 * ```typescript
 * const getMetrics = R.applySpec({
 *   sum: R.add,
 *   nested: { mul: R.multiply }
 * });
 * getMetrics(2, 4); // => { sum: 6, nested: { mul: 8 } }
 * ```
 */
export function applySpec<Obj extends Record<string, AnyFunction>>(
    obj: Obj,
): (...args: Parameters<Obj[keyof Obj]>) => { [Key in keyof Obj]: ReturnType<Obj[Key]> };
export function applySpec<T>(obj: any): (...args: unknown[]) => T;

/**
 * Takes a value and applies a function to it.
 *
 * This function is also known as the `thrush` combinator.
 *
 * @example
 * ```typescript
 * const t42 = R.applyTo(42);
 * t42(R.identity); //=> 42
 * t42(R.add(1)); //=> 43
 * ```
 */
export function applyTo<T, U>(el: T, fn: (t: T) => U): U;
export function applyTo<T>(el: T): <U>(fn: (t: T) => U) => U;

/**
 * Makes an ascending comparator function out of a function that returns a value that can be compared with `<` and `>`.
 *
 * See also {@link descend}.
 *
 * @example
 * ```typescript
 * const byAge = R.ascend(R.prop<number>('age'));
 * const people = [
 *   { name: 'Emma', age: 70 },
 *   { name: 'Peter', age: 78 },
 *   { name: 'Mikhail', age: 62 },
 * ];
 * const peopleByYoungestFirst = R.sort(byAge, people);
 *   //=> [{ name: 'Mikhail', age: 62 },{ name: 'Emma', age: 70 }, { name: 'Peter', age: 78 }]
 * ```
 */
export function ascend<T>(fn: (obj: T) => Ord, a: T, b: T): Ordering;
export function ascend<T>(fn: (obj: T) => Ord): (a: T, b: T) => Ordering;

/**
 * Makes a shallow clone of an object, setting or overriding the specified property with the given value.
 *
 * @note This copies and flattens prototype properties onto the new object as well.
 * All non-primitive properties are copied by reference.
 *
 * See also {@link dissoc}, {@link pick}.
 *
 * @example
 * ```typescript
 * R.assoc('c', 3, {a: 1, b: 2}); //=> {a: 1, b: 2, c: 3}
 * ```
 */
export function assoc<T, U>(__: Placeholder, val: T, obj: U): <K extends string>(prop: K) => K extends keyof U ? T extends U[K] ? U : Record<K, T> & Omit<U, K> : Record<K, T> & Omit<U, K>;
export function assoc<U, K extends keyof U>(prop: K, __: Placeholder, obj: U): <T>(val: T) => T extends U[K] ? U : Record<K, T> & Omit<U, K>;
export function assoc<U, K extends string>(prop: K, __: Placeholder, obj: U): <T>(val: T) => Record<K, T> & Omit<U, K>;
export function assoc<K extends keyof U, U>(prop: K, val: U[K], obj: U): U;
export function assoc<T, U, K extends string>(prop: K, val: T, obj: U): Record<K, T> & Omit<U, K>;
export function assoc<T, K extends string>(prop: K, val: T): <U>(obj: U) => Record<K, T> & Omit<U, K>;
export function assoc<K extends string>(prop: K): AssocPartialOne<K>;

/**
 * Makes a shallow clone of an object,
 * setting or overriding the nodes required to create the given path,
 * and placing the specific value at the tail end of that path.
 *
 * @note This copies and flattens prototype properties onto the new object as well.
 * All non-primitive properties are copied by reference.
 *
 * See also {@link dissocPath}.
 *
 * @example
 * ```typescript
 * R.assocPath(['a', 'b', 'c'], 42, {a: {b: {c: 0}}}); //=> {a: {b: {c: 42}}}
 *
 * // Any missing or non-object keys in path will be overridden
 * R.assocPath(['a', 'b', 'c'], 42, {a: 5}); //=> {a: {b: {c: 42}}}
 * ```
 */
export function assocPath<T, U>(__: Placeholder, val: T, obj: U): (path: Path) => U;
export function assocPath<T, U>(path: Path, __: Placeholder, obj: U): (val: T) => U;
export function assocPath<T, U>(path: Path, val: T, obj: U): U;
export function assocPath<T, U>(path: Path, val: T): (obj: U) => U;
export function assocPath<T, U>(path: Path): _.F.Curry<(a: T, b: U) => U>;

/**
 * Wraps a function of any arity (including nullary) in a function that accepts exactly 2
 * parameters. Any extraneous parameters will not be passed to the supplied function.
 *
 * See also {@link nAry}, {@link unary}.
 *
 * @example
 * ```typescript
 * const takesThreeArgs = function(a: number, b: number, c: number) {
 *   return [a, b, c];
 * };
 * takesThreeArgs.length; //=> 3
 * takesThreeArgs(1, 2, 3); //=> [1, 2, 3]
 *
 * const takesTwoArgs = R.binary(takesThreeArgs);
 * takesTwoArgs.length; //=> 2
 * // Only 2 arguments are passed to the wrapped function
 * // @ts-expect-error TypeScript is designed to not let you do this
 * takesTwoArgs(1, 2, 3); //=> [1, 2, undefined]
 * ```
 */
export function binary<T extends AnyFunction>(fn: T): (...arg: _.T.Take<Parameters<T>, '2'>) => ReturnType<T>;

/**
 * Creates a function that is bound to a context.
 *
 * @note `R.bind` does not provide the additional argument-binding capabilities of `Function.prototype.bind`.
 *
 * @example
 * ```typescript
 * const log = R.bind(console.log, console);
 * R.pipe(R.assoc('a', 2), R.tap(log), R.assoc('a', 3))({a: 1}); //=> {a: 3}
 * // logs {a: 2}
 * ```
 */
export function bind<F extends AnyFunction, T>(fn: F, thisObj: T): (...args: Parameters<F>) => ReturnType<F>;
export function bind<F extends AnyFunction, T>(fn: F): (thisObj: T) => (...args: Parameters<F>) => ReturnType<F>;

/**
 * A function which calls the two provided functions and returns the `&&` of the
 * results. It returns the result of the first function if it is falsy and
 * the result of the second function otherwise.
 *
 * @note This is short-circuited,
 * meaning that the second function will not be invoked if the first returns a falsy value.
 *
 * In addition to functions, `R.both` also accepts any fantasy-land compatible applicative functor.
 *
 * See also {@link either}, {@link and}.
 *
 * @example
 * ```typescript
 * const gt10 = R.gt(R.__, 10)
 * const lt20 = R.lt(R.__, 20)
 * const f = R.both(gt10, lt20);
 * f(15); //=> true
 * f(30); //=> false
 * ```
 */
export function both<T, TF1 extends T, TF2 extends T>(
    pred1: PredTypeguard<T, TF1>,
    pred2: PredTypeguard<T, TF2>,
): (a: T) => a is TF1 & TF2;
export function both<T extends Pred>(pred1: T, pred2: T): T;
export function both<T extends Pred>(pred1: T): (pred2: T) => T;

// NOTE: It is currently difficult to use it as a converging function for `R.converge`
/**
 * Returns the result of calling its first argument with the remaining arguments.
 * This is occasionally useful as a converging function for {@link converge `R.converge`}:
 * the first branch can produce a function
 * while the remaining branches produce values to be passed to that function as its arguments.
 *
 * See also {@link apply}.
 *
 * @example
 * ```typescript
 * R.call<(a: number, b: number) => number>(R.add, 1, 2); //=> 3
 *
 * const indentN = R.pipe(
 *   R.repeat(' '),
 *   R.join(''),
 *   R.replace(/^(?!$)/gm)
 * );
 * ```
 */
export function call<T extends AnyFunction>(fn: T, ...args: Parameters<T>): ReturnType<T>;

/**
 * `chain` maps a function over a list and concatenates the results. `chain` is also known as `flatMap` in some libraries.
 *
 * Dispatches to the `chain` method of the second argument, if present, according to the FantasyLand Chain spec.
 *
 * If second argument is a function, `chain(f, g)(x)` is equivalent to `f(g(x), x)`.
 *
 * Acts as a transducer if a transformer is given in list position.
 *
 * See also {@link transduce}.
 *
 * @example
 * ```typescript
 * const duplicate = <T>(n: T) => [n, n];
 * R.chain(duplicate, [1, 2, 3]); //=> [1, 1, 2, 2, 3, 3]
 *
 * R.chain(R.append, R.head)([1, 2, 3]); //=> [1, 2, 3, 1]
 * ```
 */
export function chain<A, B, T = never>(fn: (n: A) => readonly B[], list: readonly A[]): B[];
export function chain<A, B, T = never>(fn: (n: A) => readonly B[]): (list: readonly A[]) => B[];

export function chain<A, Ma extends { chain: (fn: (a: A) => Mb) => Mb }, Mb>(fn: (a: A) => Mb, monad: Ma): Mb;
export function chain<A, Ma extends { chain: (fn: (a: A) => Mb) => Mb }, Mb>(fn: (a: A) => Mb): (monad: Ma) => Mb;

export function chain<A, B, R>(aToMb: (a: A, r: R) => B, Ma: (r: R) => A): (r: R) => B;
export function chain<A, B, R>(aToMb: (a: A, r: R) => B): (Ma: (r: R) => A) => (r: R) => B;

/**
 * Restricts a number to be within a range.
 * Also works for other ordered types such as strings and `Date`s.
 *
 * @example
 * ```typescript
 * R.clamp(1, 10, -5) // => 1
 * R.clamp(1, 10, 15) // => 10
 * R.clamp(1, 10, 4)  // => 4
 * ```
 */
export function clamp<T>(min: T, max: T, value: T): T;
export function clamp<T>(min: T, max: T): (value: T) => T;
export function clamp<T>(min: T): (max: T, value: T) => T;
export function clamp<T>(min: T): (max: T) => (value: T) => T;

/**
 * Creates a deep copy of the source that can be used in place of the source object without retaining any references to it.
 * The source object may contain (nested) `Array`s and `Object`s, numbers, strings, booleans and `Date`s.
 * `Functions` are assigned by reference rather than copied.
 *
 * Dispatches to a `clone` method if present.
 *
 * Note that if the source object has multiple nodes that share a reference,
 * the returned object will have the same structure,
 * but the references will be pointed to the location within the cloned value.
 *
 * @example
 * ```typescript
 * const objects = [{}, {}, {}];
 * const objectsClone = R.clone(objects);
 * objects === objectsClone; //=> false
 * objects[0] === objectsClone[0]; //=> false
 * ```
 */
export function clone<T>(value: T): T;
export function clone<T>(value: readonly T[]): T[];

/**
 * Splits a list into sub-lists,
 * based on the result of calling a key-returning function on each element,
 * and grouping the results according to values returned.
 *
 * See also {@link groupBy}, {@link partition}.
 *
 * @example
 * ```typescript
 * R.collectBy(R.prop('type'), [
 *   {type: 'breakfast', item: '☕️'},
 *   {type: 'lunch', item: '🌯'},
 *   {type: 'dinner', item: '🍝'},
 *   {type: 'breakfast', item: '🥐'},
 *   {type: 'lunch', item: '🍕'}
 * ]);
 *
 * // [ [ {type: 'breakfast', item: '☕️'},
 * //     {type: 'breakfast', item: '🥐'} ],
 * //   [ {type: 'lunch', item: '🌯'},
 * //     {type: 'lunch', item: '🍕'} ],
 * //   [ {type: 'dinner', item: '🍝'} ] ]
 * ```
 */
export function collectBy<T, K extends PropertyKey>(keyFn: (value: T) => K, list: readonly T[]): T[][];
export function collectBy<T, K extends PropertyKey>(keyFn: (value: T) => K): (list: readonly T[]) => T[][];

/**
 * Makes a comparator function out of a function that reports whether the first element is less than the second.
 *
 * @example
 * ```typescript
 * type Person = { name: string; age: number; };
 *
 * const byAge = R.comparator<Person>((a, b) => a.age < b.age);
 * const people = [
 *   { name: 'Emma', age: 70 },
 *   { name: 'Peter', age: 78 },
 *   { name: 'Mikhail', age: 62 },
 * ];
 * const peopleByIncreasingAge = R.sort(byAge, people);
 *   //=> [{ name: 'Mikhail', age: 62 },{ name: 'Emma', age: 70 }, { name: 'Peter', age: 78 }]
 * ```
 */
export function comparator<T>(pred: (a: T, b: T) => boolean): (x: T, y: T) => Ordering;

/**
 * Takes a function `f` and returns a function `g` such that
 * if called with the same arguments
 * when `f` returns a truthy value, `g` returns `false`
 * and when `f` returns a falsy value `g` returns `true`.
 *
 * `R.complement` may be applied to any functor.
 *
 * See also {@link not}.
 *
 * @example
 * ```typescript
 * const isNotNil = R.complement(R.isNil);
 * R.isNil(null); //=> true
 * isNotNil(null); //=> false
 * R.isNil(7); //=> false
 * isNotNil(7); //=> true
 * ```
 */
export function complement<T, TFiltered extends T>(
    pred: (value: T) => value is TFiltered,
): (value: T) => value is Exclude<T, TFiltered>;
export function complement<TArgs extends any[]>(pred: (...args: TArgs) => unknown): (...args: TArgs) => boolean;

/**
 * Performs right-to-left function composition.
 * The rightmost function may have any arity;
 * the remaining functions must be unary.
 *
 * @note The result of `R.compose` is not automatically curried.
 *
 * See also {@link pipe}.
 *
 * @example
 * ```typescript
 * const classyGreeting = (firstName: string, lastName: string) => "The name's " + lastName + ", " + firstName + " " + lastName
 * const yellGreeting = R.compose(R.toUpper, classyGreeting);
 * yellGreeting('James', 'Bond'); //=> "THE NAME'S BOND, JAMES BOND"
 *
 * R.compose(Math.abs, R.add(1), R.multiply(2))(-4) //=> 7
 * ```
 */
export function compose<TArgs extends any[], R1, R2, R3, R4, R5, R6, R7, TResult>(
    ...func: [
        fnLast: (a: any) => TResult,
        ...func: Array<(a: any) => any>,
        f7: (a: R6) => R7,
        f6: (a: R5) => R6,
        f5: (a: R4) => R5,
        f4: (a: R3) => R4,
        f3: (a: R2) => R3,
        f2: (a: R1) => R2,
        f1: (...args: TArgs) => R1,
    ]
): (...args: TArgs) => TResult; // fallback overload if number of composed functions greater than 7
export function compose<TArgs extends any[], R1, R2, R3, R4, R5, R6, R7>(
    f7: (a: R6) => R7,
    f6: (a: R5) => R6,
    f5: (a: R4) => R5,
    f4: (a: R3) => R4,
    f3: (a: R2) => R3,
    f2: (a: R1) => R2,
    f1: (...args: TArgs) => R1,
): (...args: TArgs) => R7;
export function compose<TArgs extends any[], R1, R2, R3, R4, R5, R6, R7>(
    f7: (a: R6) => R7,
    f6: (a: R5) => R6,
    f5: (a: R4) => R5,
    f4: (a: R3) => R4,
    f3: (a: R2) => R3,
    f2: (a: R1) => R2,
    f1: (...args: TArgs) => R1,
): (...args: TArgs) => R7;
export function compose<TArgs extends any[], R1, R2, R3, R4, R5, R6>(
    f6: (a: R5) => R6,
    f5: (a: R4) => R5,
    f4: (a: R3) => R4,
    f3: (a: R2) => R3,
    f2: (a: R1) => R2,
    f1: (...args: TArgs) => R1,
): (...args: TArgs) => R6;
export function compose<TArgs extends any[], R1, R2, R3, R4, R5>(
    f5: (a: R4) => R5,
    f4: (a: R3) => R4,
    f3: (a: R2) => R3,
    f2: (a: R1) => R2,
    f1: (...args: TArgs) => R1,
): (...args: TArgs) => R5;
export function compose<TArgs extends any[], R1, R2, R3, R4>(
    f4: (a: R3) => R4,
    f3: (a: R2) => R3,
    f2: (a: R1) => R2,
    f1: (...args: TArgs) => R1,
): (...args: TArgs) => R4;
export function compose<TArgs extends any[], R1, R2, R3>(
    f3: (a: R2) => R3,
    f2: (a: R1) => R2,
    f1: (...args: TArgs) => R1,
): (...args: TArgs) => R3;
export function compose<TArgs extends any[], R1, R2>(
    f2: (a: R1) => R2,
    f1: (...args: TArgs) => R1,
): (...args: TArgs) => R2;
export function compose<TArgs extends any[], R1>(f1: (...args: TArgs) => R1): (...args: TArgs) => R1;

/**
 * Performs right-to-left function composition using transforming function.
 * The last function may have any arity; the remaining functions must be unary.
 *
 * @note The result of `R.composeWith` is not automatically curried.
 * The transforming function is not used on the last argument.
 *
 * See also {@link compose}, {@link pipeWith}.
 *
 * @example
 * ```typescript
 * const composeWhileNotNil = R.composeWith((f, res) => R.isNil(res) ? res : f(res));
 *
 * composeWhileNotNil([R.inc, R.prop('age')])({age: 1}) //=> 2
 * ```
 */
export function composeWith<TArgs extends any[], TResult>(
    transformer: (fn: AnyFunction, intermediatResult: any) => any,
    fns: AtLeastOneFunctionsFlowFromRightToLeft<TArgs, TResult>,
): (...args: TArgs) => TResult;
export function composeWith(
    transformer: (fn: AnyFunction, intermediatResult: any) => any,
): <TArgs extends any[], TResult>(
    fns: AtLeastOneFunctionsFlowFromRightToLeft<TArgs, TResult>,
) => (...args: TArgs) => TResult;

/**
 * Returns the result of concatenating the given lists or strings.
 *
 * @note `R.concat` expects both arguments to be of the same type,
 * unlike the native `Array.prototype.concat` method.
 * It will throw an error if you concat an `Array` with a non-`Array` value.
 *
 * Dispatches to the `concat` method of the first argument, if present.
 * Can also concatenate two members of a fantasy-land compatible semigroup.
 *
 * @example
 * ```typescript
 * R.concat('ABC', 'DEF'); // 'ABCDEF'
 * R.concat([4, 5, 6], [1, 2, 3]); //=> [4, 5, 6, 1, 2, 3]
 * R.concat([], []); //=> []
 * ```
 */
export function concat(
    placeholder: Placeholder,
): (<L1 extends any[], L2 extends any[]>(list1: L1, list2: L2) => [...L1, ...L2]) &
    (<S1 extends string, S2 extends string>(s1: S1, s2: S2) => `${S1}${S2}`);
export function concat<L2 extends any[]>(
    placeholder: Placeholder,
    list2: L2,
): <L1 extends any[]>(list1: L1) => [...L1, ...L2];
export function concat<S2 extends string>(
    placeholder: Placeholder,
    s2: S2,
): <S1 extends string>(s1: S1) => `${S1}${S2}`;
export function concat<L1 extends any[]>(list1: L1): <L2 extends any[]>(list2: L2) => [...L1, ...L2];
export function concat<S1 extends string>(s1: S1): <S2 extends string>(s2: S2) => `${S1}${S2}`;
export function concat<L1 extends any[], L2 extends any[]>(list1: L1, list2: L2): [...L1, ...L2];
export function concat<S1 extends string, S2 extends string>(s1: S1, s2: S2): `${S1}${S2}`;
export function concat(s1: string, s2: string): string;
export function concat(s1: string): (s2: string) => string;

/**
 * Returns a function, `fn`, which encapsulates `if/else, if/else, ...` logic.
 * `R.cond` takes a list of [predicate, transformer] pairs. All of the arguments
 * to `fn` are applied to each of the predicates in turn until one returns a
 * "truthy" value, at which point `fn` returns the result of applying its
 * arguments to the corresponding transformer. If none of the predicates
 * matches, `fn` returns undefined.
 *
 * @note This is not a direct substitute for a `switch` statement.
 * Remember that both elements of every pair passed to `cond` are *functions*,
 * and `cond` returns a function.
 *
 * @note When using this function with a typeguard as predicate,
 * **all** predicates in all pairs must be typeguards.
 *
 * See also {@link ifElse}, {@link unless}, {@link when}.
 *
 * @example
 * ```typescript
 * const fn = R.cond([
 *   [R.equals(0),   R.always('water freezes at 0°C')],
 *   [R.equals(100), R.always('water boils at 100°C')],
 *   [R.T,           temp => 'nothing special happens at ' + temp + '°C']
 * ]);
 * fn(0); //=> 'water freezes at 0°C'
 * fn(50); //=> 'nothing special happens at 50°C'
 * fn(100); //=> 'water boils at 100°C'
 * ```
 */
export function cond<T, TF1 extends T, R>(pairs: [CondPairTypeguard<T, TF1, R>]): (value: T) => R;
export function cond<T, TF1 extends T, TF2 extends T, R>(
    pairs: [CondPairTypeguard<T, TF1, R>, CondPairTypeguard<T, TF2, R>],
): (value: T) => R;
export function cond<T, TF1 extends T, TF2 extends T, TF3 extends T, R>(
    pairs: [CondPairTypeguard<T, TF1, R>, CondPairTypeguard<T, TF2, R>, CondPairTypeguard<T, TF3, R>],
): (value: T) => R;
export function cond<T, TF1 extends T, TF2 extends T, TF3 extends T, TF4 extends T, R>(
    pairs: [
        CondPairTypeguard<T, TF1, R>,
        CondPairTypeguard<T, TF2, R>,
        CondPairTypeguard<T, TF3, R>,
        CondPairTypeguard<T, TF4, R>,
    ],
): (value: T) => R;
export function cond<T, TF1 extends T, TF2 extends T, TF3 extends T, TF4 extends T, TF5 extends T, R>(
    pairs: [
        CondPairTypeguard<T, TF1, R>,
        CondPairTypeguard<T, TF2, R>,
        CondPairTypeguard<T, TF3, R>,
        CondPairTypeguard<T, TF4, R>,
        CondPairTypeguard<T, TF5, R>,
    ],
): (value: T) => R;
export function cond<T, TF1 extends T, TF2 extends T, TF3 extends T, TF4 extends T, TF5 extends T, TF6 extends T, R>(
    pairs: [
        CondPairTypeguard<T, TF1, R>,
        CondPairTypeguard<T, TF2, R>,
        CondPairTypeguard<T, TF3, R>,
        CondPairTypeguard<T, TF4, R>,
        CondPairTypeguard<T, TF5, R>,
        CondPairTypeguard<T, TF6, R>,
    ],
): (value: T) => R;
export function cond<
    T,
    TF1 extends T,
    TF2 extends T,
    TF3 extends T,
    TF4 extends T,
    TF5 extends T,
    TF6 extends T,
    TF7 extends T,
    R,
>(
    pairs: [
        CondPairTypeguard<T, TF1, R>,
        CondPairTypeguard<T, TF2, R>,
        CondPairTypeguard<T, TF3, R>,
        CondPairTypeguard<T, TF4, R>,
        CondPairTypeguard<T, TF5, R>,
        CondPairTypeguard<T, TF6, R>,
        CondPairTypeguard<T, TF7, R>,
    ],
): (value: T) => R;
export function cond<
    T,
    TF1 extends T,
    TF2 extends T,
    TF3 extends T,
    TF4 extends T,
    TF5 extends T,
    TF6 extends T,
    TF7 extends T,
    TF8 extends T,
    R,
>(
    pairs: [
        CondPairTypeguard<T, TF1, R>,
        CondPairTypeguard<T, TF2, R>,
        CondPairTypeguard<T, TF3, R>,
        CondPairTypeguard<T, TF4, R>,
        CondPairTypeguard<T, TF5, R>,
        CondPairTypeguard<T, TF6, R>,
        CondPairTypeguard<T, TF7, R>,
        CondPairTypeguard<T, TF8, R>,
    ],
): (value: T) => R;
export function cond<
    T,
    TF1 extends T,
    TF2 extends T,
    TF3 extends T,
    TF4 extends T,
    TF5 extends T,
    TF6 extends T,
    TF7 extends T,
    TF8 extends T,
    TF9 extends T,
    R,
>(
    pairs: [
        CondPairTypeguard<T, TF1, R>,
        CondPairTypeguard<T, TF2, R>,
        CondPairTypeguard<T, TF3, R>,
        CondPairTypeguard<T, TF4, R>,
        CondPairTypeguard<T, TF5, R>,
        CondPairTypeguard<T, TF6, R>,
        CondPairTypeguard<T, TF7, R>,
        CondPairTypeguard<T, TF8, R>,
        CondPairTypeguard<T, TF9, R>,
    ],
): (value: T) => R;
export function cond<
    T,
    TF1 extends T,
    TF2 extends T,
    TF3 extends T,
    TF4 extends T,
    TF5 extends T,
    TF6 extends T,
    TF7 extends T,
    TF8 extends T,
    TF9 extends T,
    TF10 extends T,
    R,
>(
    pairs: [
        CondPairTypeguard<T, TF1, R>,
        CondPairTypeguard<T, TF2, R>,
        CondPairTypeguard<T, TF3, R>,
        CondPairTypeguard<T, TF4, R>,
        CondPairTypeguard<T, TF5, R>,
        CondPairTypeguard<T, TF6, R>,
        CondPairTypeguard<T, TF7, R>,
        CondPairTypeguard<T, TF8, R>,
        CondPairTypeguard<T, TF9, R>,
        CondPairTypeguard<T, TF10, R>,
    ],
): (value: T) => R;
export function cond<T extends any[], R>(pairs: ReadonlyArray<CondPair<T, R>>): (...args: T) => R;

/**
 * Wraps a constructor function inside a curried function that can be called with the same arguments and returns the same type.
 *
 * See also {@link invoker}.
 *
 * @example
 * ```typescript
 * // Constructor function
 * class Animal {
 *   constructor(public kind: string) {}
 *
 *   sighting() {
 *     return "It's a " + this.kind + "!";
 *   }
 * }
 *
 * const AnimalConstructor = R.construct(Animal)
 *
 * // Notice we no longer need the 'new' keyword:
 * AnimalConstructor('Pig'); //=> {"kind": "Pig", "sighting": function (){...}};
 *
 * const animalTypes = ["Lion", "Tiger", "Bear"];
 * const animalSighting = R.invoker(0, 'sighting');
 * const sightNewAnimal = R.compose(animalSighting, AnimalConstructor);
 * R.map(sightNewAnimal, animalTypes); //=> ["It's a Lion!", "It's a Tiger!", "It's a Bear!"]
 * ```
 */
export function construct<A extends any[], T>(
    constructor: { new (...args: A): T } | ((...args: A) => T),
): _.F.Curry<(...args: A) => T>;

// NOTE: Example doesn't work with this typing
/**
 * Wraps a constructor function inside a curried function that can be called with the same arguments and returns the same type.
 * The arity of the function returned is specified to allow using variadic constructor functions.
 */
export function constructN<A extends any[], T, N extends number>(
    n: N,
    constructor: { new (...args: A): T } | ((...args: A) => T),
): _.F.Curry<(...args: mergeArrWithLeft<Tuple<any, N>, A>) => T>;

// NOTE: Example doesn't work with this typing
/**
 * Accepts a converging function and a list of branching functions and returns a new function.
 * When invoked, this new function is applied to some arguments,
 * each branching function is applied to those same arguments.
 * The results of each branching function are passed as arguments to the converging function
 * to produce the return value.
 *
 * See also {@link useWith}.
 */
export function converge<
    TResult,
    FunctionsList extends ReadonlyArray<Fn> &
        IfFunctionsArgumentsDoNotOverlap<_Fns, 'Functions arguments types must overlap'>,
    _Fns extends ReadonlyArray<Fn> = FunctionsList,
>(
    converging: (...args: ReturnTypesOfFns<FunctionsList>) => TResult,
    branches: FunctionsList,
): _.F.Curry<(...args: LargestArgumentsList<FunctionsList>) => TResult>;
export function converge<
    CArgs extends ReadonlyArray<any>,
    TResult,
    FunctionsList extends readonly [
        ...{
            [Index in keyof CArgs]: (...args: ReadonlyArray<any>) => CArgs[Index];
        },
    ] &
        IfFunctionsArgumentsDoNotOverlap<_Fns, 'Functions arguments types must overlap'>,
    _Fns extends ReadonlyArray<Fn> = FunctionsList,
>(
    converging: (...args: CArgs) => TResult,
    branches: FunctionsList,
): _.F.Curry<(...args: LargestArgumentsList<FunctionsList>) => TResult>;

/**
 * Returns the number of items in a given `list` matching the predicate `f`.
 *
 * @example
 * ```typescript
 * const even = (x: number) => x % 2 == 0;
 *
 * R.count(even, [1, 2, 3, 4, 5]); // => 2
 * R.map(R.count(even), [[1, 1, 1], [2, 3, 4, 5], [6]]); // => [0, 2, 1]
 * ```
 */
export function count<T>(fn: (a: T) => boolean, list: readonly T[]): number;
export function count<T>(fn: (a: T) => boolean): (list: readonly T[]) => number;

/**
 * Counts the elements of a list according to how many match each value of a key generated by the supplied function.
 * Returns an object mapping the keys produced by `fn` to the number of occurrences in the list.
 * Note that all keys are coerced to strings because of how JavaScript objects work.
 *
 * Acts as a transducer if a transformer is given in list position.
 *
 * See also {@link transduce}.
 *
 * @example
 * ```typescript
 * const numbers = [1.0, 1.1, 1.2, 2.0, 3.0, 2.2];
 * R.countBy(Math.floor)(numbers);    //=> {'1': 3, '2': 2, '3': 1}
 *
 * const letters = ['a', 'b', 'A', 'a', 'B', 'c'];
 * R.countBy(R.toLower)(letters);   //=> {'a': 3, 'b': 2, 'c': 1}
 * ```
 */
export function countBy<T>(fn: (a: T) => string | number, list: readonly T[]): { [index: string]: number };
export function countBy<T>(fn: (a: T) => string | number): (list: readonly T[]) => { [index: string]: number };

/**
 * Returns a curried equivalent of the provided function.
 *
 * See also {@link curryN}, {@link partial}.
 *
 * The curried function has two unusual capabilities.
 *
 * First, its arguments needn't be provided one at a time.
 * If `f` is a ternary function and `g` is `R.curry(f)`, the following are equivalent:
 *  - `g(1)(2)(3)`
 *  - `g(1)(2, 3)`
 *  - `g(1, 2)(3)`
 *  - `g(1, 2, 3)`
 *
 * Secondly, the special placeholder value `R.__` may be used to specify "gaps",
 * allowing partial application of any combination of arguments,
 * regardless of their positions.
 * If `g` is as above and `_` is `R.__`, the following are equivalent:
 *  - `g(1, 2, 3)`
 *  - `g(_, 2, 3)(1)`
 *  - `g(_, _, 3)(1)(2)`
 *  - `g(_, _, 3)(1, 2)`
 *  - `g(_, 2)(1)(3)`
 *  - `g(_, 2)(1, 3)`
 *  - `g(_, 2)(_, 3)(1)`
 *
 * @example
 * ```typescript
 * const addFourNumbers = (a: number, b: number, c: number, d: number) => a + b + c + d;
 *
 * const curriedAddFourNumbers = R.curry(addFourNumbers);
 * const f = curriedAddFourNumbers(1, 2);
 * const g = f(3);
 * g(4); //=> 10
 * ```
 */
export function curry<F extends AnyFunction>(f: F): _.F.Curry<F>;

/**
 * Returns a curried equivalent of the provided function, with the specified arity.
 *
 * See also {@link curry}.
 *
 * The curried function has two unusual capabilities.
 *
 * First, its arguments needn't be provided one at a time.
 * If `f` is a ternary function and `g` is `R.curry(f)`, the following are equivalent:
 *  - `g(1)(2)(3)`
 *  - `g(1)(2, 3)`
 *  - `g(1, 2)(3)`
 *  - `g(1, 2, 3)`
 *
 * Secondly, the special placeholder value `R.__` may be used to specify "gaps",
 * allowing partial application of any combination of arguments,
 * regardless of their positions.
 * If `g` is as above and `_` is `R.__`, the following are equivalent:
 *  - `g(1, 2, 3)`
 *  - `g(_, 2, 3)(1)`
 *  - `g(_, _, 3)(1)(2)`
 *  - `g(_, _, 3)(1, 2)`
 *  - `g(_, 2)(1)(3)`
 *  - `g(_, 2)(1, 3)`
 *  - `g(_, 2)(_, 3)(1)`
 *
 * @example
 * ```typescript
 * const sumArgs = (...args: number[]) => R.sum(args);
 *
 * const curriedAddFourNumbers = R.curryN(4, sumArgs);
 * const f = curriedAddFourNumbers(1, 2);
 * const g = f(3);
 * g(4); //=> 10
 * ```
 */
export function curryN<N extends number, F extends AnyFunction>(
    length: N,
    fn: F,
): _.F.Curry<(...args: _.T.Take<Parameters<F>, _.N.NumberOf<N>>) => ReturnType<F>>;
export function curryN<N extends number>(
    length: N,
): <F extends AnyFunction>(fn: F) => _.F.Curry<(...args: _.T.Take<Parameters<F>, _.N.NumberOf<N>>) => ReturnType<F>>;

/**
 * Decrements its argument.
 *
 * See also {@link inc}.
 *
 * @example
 * ```typescript
 * R.dec(42); //=> 41
 * ```
 */
export function dec(n: number): number;

/**
 * Returns the second argument if it is not `null`, `undefined` or `NaN`; otherwise the first argument is returned.
 *
 * @example
 * ```typescript
 * const defaultTo42 = R.defaultTo(42);
 *
 * defaultTo42(null);      //=> 42
 * defaultTo42(undefined); //=> 42
 * defaultTo42(false);     //=> false
 * defaultTo42('Ramda');   //=> 'Ramda'
 * // parseInt('string') results in NaN
 * defaultTo42(parseInt('string')); //=> 42
 * ```
 */
export function defaultTo<T, U>(a: T, b: U | null | undefined): T | U;
export function defaultTo<T>(a: T): <U>(b: U | null | undefined) => T | U;

/**
 * Makes a descending comparator function out of a function that returns a value that can be compared with `<` and `>`.
 *
 * See also {@link ascend}.
 *
 * @example
 * ```typescript
 * type Person = { name: string; age: number; };
 *
 * const byAge = R.descend<Person>(R.prop('age'));
 * const people = [
 *   { name: 'Emma', age: 70 },
 *   { name: 'Peter', age: 78 },
 *   { name: 'Mikhail', age: 62 },
 * ];
 * const peopleByOldestFirst = R.sort(byAge, people);
 *   //=> [{ name: 'Peter', age: 78 }, { name: 'Emma', age: 70 }, { name: 'Mikhail', age: 62 }]
 * ```
 */
export function descend<T>(fn: (obj: T) => Ord, a: T, b: T): Ordering;
export function descend<T>(fn: (obj: T) => Ord): (a: T, b: T) => Ordering;

/**
 * Finds the set (i.e. no duplicates) of all elements in the first list not contained in the second list.
 * `Object`s and `Array`s are compared in terms of value equality, not reference equality.
 *
 * See also {@link differenceWith}, {@link symmetricDifference}, {@link symmetricDifferenceWith}, {@link without}.
 *
 * @example
 * ```typescript
 * R.difference([1,2,3,4], [7,6,5,4,3]); //=> [1,2]
 * R.difference([7,6,5,4,3], [1,2,3,4]); //=> [7,6,5]
 * R.difference<{ a: number; } | { b: number; } | { c: number; }>([{a: 1}, {b: 2}], [{a: 1}, {c: 3}]) //=> [{b: 2}]
 * ```
 */
export function difference<T>(list1: readonly T[], list2: readonly T[]): T[];
export function difference<T>(list1: readonly T[]): (list2: readonly T[]) => T[];

/**
 * Finds the set (i.e. no duplicates) of all elements in the first list not contained in the second list.
 * Duplication is determined according to the value returned
 * by applying the supplied predicate to two list elements.
 *
 * See also See also {@link difference}, {@link symmetricDifference}, {@link symmetricDifferenceWith}.
 *
 * @example
 * ```typescript
 * const cmp = (x: { a: number; }, y: { a: number; }) => x.a === y.a;
 * const l1 = [{a: 1}, {a: 2}, {a: 3}];
 * const l2 = [{a: 3}, {a: 4}];
 * R.differenceWith(cmp, l1, l2); //=> [{a: 1}, {a: 2}]
 * ```
 */
export function differenceWith<T1, T2>(
    pred: (a: T1, b: T2) => boolean,
    list1: readonly T1[],
    list2: readonly T2[],
): T1[];
export function differenceWith<T1, T2>(
    pred: (a: T1, b: T2) => boolean,
): (list1: readonly T1[], list2: readonly T2[]) => T1[];
export function differenceWith<T1, T2>(
    pred: (a: T1, b: T2) => boolean,
    list1: readonly T1[],
): (list2: readonly T2[]) => T1[];

/**
 * Returns a new object that does not contain the given property.
 *
 * See also {@link assoc}, {@link omit}.
 *
 * @example
 * ```typescript
 * R.dissoc('b', {a: 1, b: 2, c: 3}); //=> {a: 1, c: 3}
 * ```
 */
export function dissoc<T extends object, K extends keyof T>(prop: K, obj: T): Omit<T, K>;
export function dissoc<K extends string | number>(prop: K): <T extends object>(obj: T) => Omit<T, K>;

/**
 * Makes a shallow clone of an object, omitting the property at the given path.
 *
 * @note This copies and flattens prototype properties onto the new object as well.
 * All non-primitive properties are copied by reference.
 *
 * @example
 * ```typescript
 * R.dissocPath(['a', 'b', 'c'], {a: {b: {c: 42}}}); //=> {a: {b: {}}}
 * ```
 */
export function dissocPath<T>(path: Path, obj: any): T;
export function dissocPath<T>(path: Path): (obj: any) => T;

/**
 * Divides two numbers. Equivalent to `a / b` but curried.
 *
 * See also {@link multiply}.
 *
 * @example
 * ```typescript
 * R.divide(71, 100); //=> 0.71
 *
 * const half = R.divide(R.__, 2);
 * half(42); //=> 21
 *
 * const reciprocal = R.divide(1);
 * reciprocal(4);   //=> 0.25
 * ```
 */
export function divide(__: Placeholder, b: number): (a: number) => number;
export function divide(__: Placeholder): (b: number, a: number) => number;
export function divide(a: number, b: number): number;
export function divide(a: number): (b: number) => number;

/**
 * Returns all but the first `n` elements of the given list, string, or transducer/transformer.
 *
 * Dispatches to the `drop` method of the second argument, if present.
 *
 * See also {@link take}, {@link transduce}, {@link dropLast}, {@link dropWhile}.
 *
 * @example
 * ```typescript
 * R.drop(1, ['foo', 'bar', 'baz']); //=> ['bar', 'baz']
 * R.drop(2, ['foo', 'bar', 'baz']); //=> ['baz']
 * R.drop(3, ['foo', 'bar', 'baz']); //=> []
 * R.drop(4, ['foo', 'bar', 'baz']); //=> []
 * R.drop(3, 'ramda');               //=> 'da'
 * ```
 */
export function drop<T>(n: number, xs: readonly T[]): T[];
export function drop(n: number, xs: string): string;
export function drop<T>(n: number): {
    (xs: string): string;
    (xs: readonly T[]): T[];
};

/**
 * Returns a list containing all but the last `n` elements of the given list.
 *
 * Acts as a transducer if a transformer is given in list position.
 *
 * See also {@link takeLast}, {@link drop}, {@link dropWhile}, {@link dropLastWhile}, {@link transduce}.
 *
 * @example
 * ```typescript
 * R.dropLast(1, ['foo', 'bar', 'baz']); //=> ['foo', 'bar']
 * R.dropLast(2, ['foo', 'bar', 'baz']); //=> ['foo']
 * R.dropLast(3, ['foo', 'bar', 'baz']); //=> []
 * R.dropLast(4, ['foo', 'bar', 'baz']); //=> []
 * R.dropLast(3, 'ramda');               //=> 'ra'
 * ```
 */
export function dropLast<T>(n: number, xs: readonly T[]): T[];
export function dropLast(n: number, xs: string): string;
export function dropLast<T>(n: number): {
    (xs: readonly T[]): T[];
    (xs: string): string;
};

/**
 * Returns a new list excluding all the tailing elements of a given list which satisfy the supplied predicate function.
 * It passes each value from the right to the supplied predicate function,
 * skipping elements until the predicate function returns a falsy value.
 *
 * Acts as a transducer if a transformer is given in list position.
 *
 * See also {@link takeLastWhile}, {@link addIndex}, {@link drop}, {@link dropWhile}, {@link transduce}.
 *
 * @example
 * ```typescript
 * const lteThree = (x: number) => x <= 3;
 *
 * R.dropLastWhile(lteThree, [1, 2, 3, 4, 3, 2, 1]); //=> [1, 2, 3, 4]
 *
 * R.dropLastWhile(x => x !== 'd', 'Ramda'); //=> 'Ramd'
 * ```
 */
export function dropLastWhile<T>(fn: (a: T) => boolean, list: readonly T[]): T[];
export function dropLastWhile<T>(fn: (a: T) => boolean): (list: readonly T[]) => T[];

/**
 * Returns a new list without any consecutively repeating elements.
 * {@link equals `R.equals`} is used to determine equality.
 *
 * Acts as a transducer if a transformer is given in list position.
 *
 * See also {@link transduce}.
 *
 * @example
 * ```typescript
 * R.dropRepeats([1, 1, 1, 2, 3, 4, 4, 2, 2]); //=> [1, 2, 3, 4, 2]
 * ```
 */
export function dropRepeats<T>(list: readonly T[]): T[];

/**
 * Returns a new list without any consecutively repeating elements.
 * Equality is determined by applying the supplied predicate to each pair of consecutive elements.
 * The first element in a series of equal elements will be preserved.
 *
 * Acts as a transducer if a transformer is given in list position.
 *
 * See also {@link transduce}.
 *
 * @example
 * ```typescript
 * const l = [1, -1, 1, 3, 4, -4, -4, -5, 5, 3, 3];
 * R.dropRepeatsWith(R.eqBy(Math.abs), l); //=> [1, 3, 4, -5, 3]
 * ```
 */
export function dropRepeatsWith<T>(predicate: (left: T, right: T) => boolean, list: readonly T[]): T[];
export function dropRepeatsWith<T>(predicate: (left: T, right: T) => boolean): (list: readonly T[]) => T[];

/**
 * Returns a new list excluding the leading elements of a given list
 * which satisfy the supplied predicate function.
 * It passes each value to the supplied predicate function,
 * skipping elements while the predicate function returns a truthy value.
 *
 * Dispatches to the `dropWhile` method of the second argument, if present.
 *
 * Acts as a transducer if a transformer is given in list position.
 *
 * See also {@link takeWhile}, {@link addIndex}, {@link transduce}.
 *
 * @example
 * ```typescript
 * const lteTwo = (x: number) => x <= 2;
 *
 * R.dropWhile(lteTwo, [1, 2, 3, 4, 3, 2, 1]); //=> [3, 4, 3, 2, 1]
 *
 * R.dropWhile(x => x !== 'd' , 'Ramda'); //=> 'da'
 * ```
 */
export function dropWhile<T>(fn: (a: T) => boolean, list: readonly T[]): T[];
export function dropWhile<T>(fn: (a: T) => boolean): (list: readonly T[]) => T[];

/**
 * A function wrapping calls to the two functions in an `||` operation,
 * returning the result of the first function if it is truthy
 * and the result of the second function otherwise.
 *
 * @note This is short-circuited, meaning that the second function will not be invoked if the first returns a truthy value.
 *
 * See also {@link both}, {@link or}.
 *
 * @example
 * ```typescript
 * const gt10 = (x: number) => x > 10;
 * const even = (x: number) => x % 2 === 0;
 * const f = R.either(gt10, even);
 * f(101); //=> true
 * f(8); //=> true
 * ```
 */
export function either<T extends Pred>(pred1: T, pred2: T): T;
export function either<T extends Pred>(pred1: T): (pred2: T) => T;

/**
 * Returns the empty value of its argument's type.
 * Ramda defines the empty value of `Array` (`[]`), `Object` (`{}`), string (`''`),
 * `TypedArray` (`Uint8Array []`, `Float32Array []`, etc) and arguments.
 *
 * Other types are supported if they define `<Type>.empty`, `<Type>.prototype.empty`
 * or implement the FantasyLand Monoid spec.
 *
 * Dispatches to the `empty` method of the first argument, if present.
 *
 * @example
 * ```typescript
 * R.empty([1, 2, 3]);                  //=> []
 * R.empty('unicorns');                 //=> ''
 * R.empty({x: 1, y: 2});               //=> {}
 * R.empty(Uint8Array.from([1, 2, 3])); //=> Uint8Array []
 * ```
 */
export function empty<T>(x: T): T;

/**
 * Checks if a list ends with the provided sublist.
 *
 * Similarly, checks if a string ends with the provided substring.
 *
 * See also {@link startsWith}.
 *
 * @example
 * ```typescript
 * R.endsWith('c', 'abc')                //=> true
 * R.endsWith('b', 'abc')                //=> false
 * R.endsWith(['c'], ['a', 'b', 'c'])    //=> true
 * R.endsWith(['b'], ['a', 'b', 'c'])    //=> false
 * ```
 */
export function endsWith(substr: string, str: string): boolean;
export function endsWith(substr: string): (str: string) => boolean;
export function endsWith<T>(subList: readonly T[], list: readonly T[]): boolean;
export function endsWith<T>(subList: readonly T[]): (list: readonly T[]) => boolean;

/**
 * Takes a function and two values in its domain and returns `true` if the values map to the same value in the codomain;
 * `false` otherwise.
 *
 * @example
 * ```typescript
 * R.eqBy(Math.abs, 5, -5); //=> true
 * ```
 */
export function eqBy<T>(fn: (a: T) => unknown, a: T, b: T): boolean;
export function eqBy<T>(fn: (a: T) => unknown, a: T): (b: T) => boolean;
export function eqBy<T>(fn: (a: T) => unknown): {
    (a: T, b: T): boolean;
    (a: T): (b: T) => boolean;
};

/**
 * Reports whether two objects have the same value, in {@link equals `R.equals`} terms, for the specified property.
 * Useful as a curried predicate.
 *
 * @example
 * ```typescript
 * const o1 = { a: 1, b: 2, c: 3, d: 4 };
 * const o2 = { a: 10, b: 20, c: 3, d: 40 };
 * R.eqProps('a', o1, o2); //=> false
 * R.eqProps('c', o1, o2); //=> true
 * ```
 */
export function eqProps<T, U>(prop: string, obj1: T, obj2: U): boolean;
export function eqProps<P extends string>(prop: P): <T, U>(obj1: Record<P, T>, obj2: Record<P, U>) => boolean;
export function eqProps<T>(prop: string, obj1: T): <U>(obj2: U) => boolean;

/**
 * Returns `true` if its arguments are equivalent, `false` otherwise.
 * Handles cyclical data structures.
 *
 * Dispatches symmetrically to the `equals` methods of both arguments, if present.
 *
 * @example
 * ```typescript
 * R.equals(1, 1); //=> true
 * R.equals([1, 2, 3], [1, 2, 3]); //=> true
 *
 * type Recursive = { v: Recursive; };
 *
 * const a: Recursive = {} as Recursive; a.v = a;
 * const b: Recursive = {} as Recursive; b.v = b;
 * R.equals(a, b); //=> true
 * ```
 */
export function equals<T>(__: Placeholder, b: T): (a: T) => boolean;
export function equals<T>(a: T, b: T): boolean;
export function equals<T>(a: T): (b: T) => boolean;

/**
 * Creates a new object by evolving a shallow copy of the `object`,
 * according to the functions in `transformations`.
 * All non-primitive properties are copied by reference.
 *
 * A function in `transformations` will not be invoked if its corresponding key does not exist in the evolved object.
 *
 * @example
 * ```typescript
 * const tomato = {firstName: '  Tomato ', data: {elapsed: 100, remaining: 1400}, id:123};
 * const transformations = {
 *   firstName: R.trim,
 *   lastName: R.trim, // Will not get invoked.
 *   data: {elapsed: R.add(1), remaining: R.add(-1)}
 * };
 * R.evolve(transformations, tomato); //=> {firstName: 'Tomato', data: {elapsed: 101, remaining: 1399}, id:123}
 * ```
 */
export function evolve<E extends Evolver, V extends Evolvable<E>>(transformations: E, obj: V): Evolve<V, E>;
export function evolve<E extends Evolver>(transformations: E): <V extends Evolvable<E>>(obj: V) => Evolve<V, E>;

/**
 * A function that always returns `false`.
 * Any passed in parameters are ignored.
 *
 * See also {@link T}.
 *
 * @example
 * ```typescript
 * R.F(); //=> false
 * ```
 */
export function F(...args: unknown[]): false;

/**
 * Takes a predicate and a `Filterable`,
 * and returns a new `Filterable` of the same type
 * containing the members of the given `Filterable` which satisfy the given predicate.
 * Filterable objects include plain objects or any object that has a filter method such as Array.
 *
 * Dispatches to the `filter` method of the second argument, if present.
 *
 * Acts as a transducer if a transformer is given in list position.
 *
 * See also {@link reject}, {@link transduce}, {@link addIndex}.
 *
 * @example
 * ```typescript
 * const isEven = (n: number) => n % 2 === 0;
 *
 * R.filter(isEven, [1, 2, 3, 4]); //=> [2, 4]
 *
 * R.filter(isEven, {a: 1, b: 2, c: 3, d: 4}); //=> {b: 2, d: 4}
 * ```
 */
export function filter<A, P extends A>(
    pred: (val: A) => val is P,
): {
    <B extends A>(list: readonly B[]): P[];
    <B extends A>(dict: Dictionary<B>): Dictionary<P>;
};
export function filter<T>(
    pred: (value: T) => boolean,
): <P extends T, C extends readonly P[] | Dictionary<P>>(collection: C) => C;
export function filter<T, P extends T>(pred: (val: T) => val is P, list: readonly T[]): P[];
export function filter<T, P extends T>(pred: (val: T) => val is P, dict: Dictionary<T>): Dictionary<P>;
export function filter<T, C extends readonly T[] | Dictionary<T>>(pred: (value: T) => boolean, collection: C): C;

/**
 * Returns the first element of the list which matches the predicate,
 * or `undefined` if no element matches.
 *
 * Dispatches to the `find` method of the second argument, if present.
 *
 * Acts as a transducer if a transformer is given in list position.
 *
 * See also {@link transduce}.
 *
 * @example
 * ```typescript
 * const xs = [{a: 1}, {a: 2}, {a: 3}];
 * R.find(R.propEq('a', 2))(xs); //=> {a: 2}
 * R.find(R.propEq('a', 4))(xs); //=> undefined
 * ```
 */
export function find<T, P extends T>(pred: (val: T) => val is P, list: readonly T[]): P | undefined;
export function find<T>(pred: (val: T) => boolean, list: readonly T[]): T | undefined;
export function find<T, P extends T>(pred: (val: T) => val is P): (list: readonly T[]) => P | undefined;
export function find<T>(pred: (val: T) => boolean): (list: readonly T[]) => T | undefined;

/**
 * Returns the index of the first element of the list which matches the predicate,
 * or `-1` if no element matches.
 *
 * Acts as a transducer if a transformer is given in list position.
 *
 * See also {@link indexOf}, {@link transduce}.
 *
 * @example
 * ```typescript
 * const xs = [{a: 1}, {a: 2}, {a: 3}];
 * R.findIndex(R.propEq('a', 2))(xs); //=> 1
 * R.findIndex(R.propEq('a', 4))(xs); //=> -1
 * ```
 */
export function findIndex<T>(fn: (a: T) => boolean, list: readonly T[]): number;
export function findIndex<T>(fn: (a: T) => boolean): (list: readonly T[]) => number;

/**
 * Returns the last element of the list which matches the predicate, or `undefined` if no element matches.
 *
 * Acts as a transducer if a transformer is given in list position.
 *
 * See also {@link transduce}.
 *
 * @example
 * ```typescript
 * const xs = [{a: 1, b: 0}, {a:1, b: 1}];
 * R.findLast(R.propEq('a', 1))(xs); //=> {a: 1, b: 1}
 * R.findLast(R.propEq('a', 4))(xs); //=> undefined
 * ```
 */
export function findLast<T, P extends T>(pred: (val: T) => val is P, list: readonly T[]): P | undefined;
export function findLast<T>(pred: (val: T) => boolean, list: readonly T[]): T | undefined;
export function findLast<T, P extends T>(pred: (val: T) => val is P): (list: readonly T[]) => P | undefined;
export function findLast<T>(pred: (val: T) => boolean): (list: readonly T[]) => T | undefined;

/**
 * Returns the index of the last element of the list which matches the predicate,
 * or `-1` if no element matches.
 *
 * Acts as a transducer if a transformer is given in list position.
 *
 * See also {@link lastIndexOf}, {@link transduce}.
 *
 * @example
 * ```typescript
 * const xs = [{a: 1, b: 0}, {a:1, b: 1}];
 * R.findLastIndex(R.propEq('a', 1))(xs); //=> 1
 * R.findLastIndex(R.propEq('a', 4))(xs); //=> -1
 * ```
 */
export function findLastIndex<T>(fn: (a: T) => boolean, list: readonly T[]): number;
export function findLastIndex<T>(fn: (a: T) => boolean): (list: readonly T[]) => number;

/**
 * Returns a new list by pulling every item out of it (and all its sub-arrays)
 * and putting them in a new array, depth-first.
 *
 * See also {@link unnest}.
 *
 * @example
 * ```typescript
 * R.flatten([1, 2, [3, 4], 5, [6, [7, 8, [9, [10, 11], 12]]]]);
 * //=> [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]
 * ```
 */
export function flatten<T extends readonly any[]>(list: T): _.T.Flatten<T>;

/**
 * Flips the order of the first two arguments to the given function.
 *
 * @example
 * ```typescript
 * const mergeThree = <T>(a: T, b: T, c: T) => ([] as T[]).concat(a, b, c);
 *
 * mergeThree(1, 2, 3); //=> [1, 2, 3]
 *
 * R.flip(mergeThree)(1, 2, 3); //=> [2, 1, 3]
 * ```
 */
export function flip<T, U, TResult>(fn: (arg0: T, arg1: U) => TResult): (arg1: U, arg0?: T) => TResult;
export function flip<F extends AnyFunction, P extends _.F.Parameters<F>>(
    fn: F,
): _.F.Curry<(...args: _.T.Merge<[P[1], P[0]], P>) => _.F.Return<F>>;

/**
 * Iterate over the given list, calling the given function for each element in the list.
 *
 * @note `R.forEach` does not skip deleted or unassigned indices (sparse arrays),
 * unlike the native `Array.prototype.forEach` method.
 *
 * Also note that, unlike `Array.prototype.forEach`, `R.forEach` returns the original array.
 * In some libraries this function is named `each`.
 *
 * Dispatches to the `forEach` method of the second argument, if present.
 *
 * @example
 * ```typescript
 * const printXPlusFive = (x: number) => console.log(x + 5);
 * R.forEach(printXPlusFive, [1, 2, 3]); //=> [1, 2, 3]
 * // logs 6
 * // logs 7
 * // logs 8
 * ```
 */
export function forEach<T>(fn: (x: T) => void, list: readonly T[]): T[];
export function forEach<T>(fn: (x: T) => void): (list: readonly T[]) => T[];
export function forEach<T>(fn: (x: T) => void, list: readonly T[]): T[];
export function forEach<T>(fn: (x: T) => void): (list: readonly T[]) => T[];

/**
 * Iterate over the given object, calling the given function for each key and value in the object.
 *
 * @example
 * ```typescript
 * const printKeyConcatValue = (value: unknown, key: string) => console.log(key + ':' + value);
 * R.forEachObjIndexed(printKeyConcatValue, {x: 1, y: 2}); //=> {x: 1, y: 2}
 * // logs x:1
 * // logs y:2
 * ```
 */
export function forEachObjIndexed<T>(fn: (value: T[keyof T], key: keyof T, obj: T) => void, obj: T): T;
export function forEachObjIndexed<T>(fn: (value: T[keyof T], key: keyof T, obj: T) => void): (obj: T) => T;

/**
 * Creates a new object from a list key-value pairs.
 * If a key appears in multiple pairs,
 * the rightmost pair is included in the object.
 *
 * See also {@link toPairs}, {@link pair}.
 *
 * @example
 * ```typescript
 * R.fromPairs([['a', 1], ['b', 2], ['c', 3]]); //=> {a: 1, b: 2, c: 3}
 * ```
 */
export function fromPairs<V>(
    pairs: ReadonlyArray<Readonly<KeyValuePair<string, V>>> | ReadonlyArray<Readonly<KeyValuePair<number, V>>>,
): { [index: string]: V };

/**
 * Splits a list into sub-lists stored in an object,
 * based on the result of calling a key-returning function on each element,
 * and grouping the results according to values returned.
 *
 * Dispatches to the `groupBy` method of the second argument, if present.
 *
 * Acts as a transducer if a transformer is given in list position.
 *
 * See also {@link reduceBy}, {@link indexBy}, {@link transduce}.
 *
 * @example
 * ```typescript
 * type Student = { name: string; score: number; }
 *
 * const byGrade = R.groupBy((student: Student) => {
 *   const score = student.score;
 *   return score < 65 ? 'F' :
 *          score < 70 ? 'D' :
 *          score < 80 ? 'C' :
 *          score < 90 ? 'B' : 'A';
 * });
 * const students = [{name: 'Abby', score: 84},
 *                   {name: 'Eddy', score: 58},
 *                   // ...
 *                   {name: 'Jack', score: 69}];
 * byGrade(students);
 * // {
 * //   'A': [{name: 'Dianne', score: 99}],
 * //   'B': [{name: 'Abby', score: 84}]
 * //   // ...,
 * //   'F': [{name: 'Eddy', score: 58}]
 * // }
 * ```
 */
export function groupBy<T, K extends string = string>(fn: (a: T) => K, list: readonly T[]): Record<K, T[]>;
export function groupBy<T, K extends string = string>(fn: (a: T) => K): (list: readonly T[]) => Record<K, T[]>;

/**
 * Takes a list and returns a list of lists
 * where every adjacent element of each sublist satisfies the given predicate.
 *
 * @example
 * ```typescript
 * R.groupWith(R.equals, [0, 1, 1, 2, 3, 5, 8, 13, 21])
 * //=> [[0], [1, 1], [2], [3], [5], [8], [13], [21]]
 *
 * R.groupWith((a, b) => a + 1 === b, [0, 1, 1, 2, 3, 5, 8, 13, 21])
 * //=> [[0, 1], [1, 2, 3], [5], [8], [13], [21]]
 *
 * R.groupWith((a, b) => a % 2 === b % 2, [0, 1, 1, 2, 3, 5, 8, 13, 21])
 * //=> [[0], [1, 1], [2], [3, 5], [8], [13, 21]]
 *
 * const isVowel = R.test(/^[aeiou]$/i);
 * R.groupWith(R.eqBy(isVowel), 'aestiou')
 * //=> ['ae', 'st', 'iou']
 * ```
 */
export function groupWith<T>(fn: (x: T, y: T) => boolean): (list: readonly T[]) => T[][];
export function groupWith<T>(fn: (x: T, y: T) => boolean, list: readonly T[]): T[][];
export function groupWith<T>(fn: (x: T, y: T) => boolean, list: string): string[];

/**
 * Returns `true` if the first parameter is greater than the second; `false` otherwise.
 *
 * See also {@link gte}, {@link lt}, {@link lte}.
 *
 * @example
 * ```typescript
 * R.gt(2, 1); //=> true
 * R.gt(2, 2); //=> false
 * R.gt(2, 3); //=> false
 * R.gt('a', 'z'); //=> false
 * R.gt('z', 'a'); //=> true
 * ```
 */
export function gt(__: Placeholder, b: number): (a: number) => boolean;
export function gt(__: Placeholder): (b: number, a: number) => boolean;
export function gt(a: number, b: number): boolean;
export function gt(a: string, b: string): boolean;
export function gt(a: number): (b: number) => boolean;

/**
 * Returns `true` if the first parameter is greater than or equal to the second; `false` otherwise.
 *
 * See also {@link gt}, {@link lt}, {@link lte}.
 *
 * @example
 * ```typescript
 * R.gte(2, 1); //=> true
 * R.gte(2, 2); //=> true
 * R.gte(2, 3); //=> false
 * R.gte('a', 'z'); //=> false
 * R.gte('z', 'a'); //=> true
 * ```
 */
export function gte(__: Placeholder, b: number): (a: number) => boolean;
export function gte(__: Placeholder): (b: number, a: number) => boolean;
export function gte(a: number, b: number): boolean;
export function gte(a: string, b: string): boolean;
export function gte(a: number): (b: number) => boolean;

/**
 * Returns whether or not an object has an own property with the specified name.
 *
 * @example
 * ```typescript
 * const hasName = R.has('name');
 * hasName({name: 'alice'});   //=> true
 * hasName({name: 'bob'});     //=> true
 * hasName({});                //=> false
 *
 * const point = {x: 0, y: 0};
 * const pointHas = R.has(R.__, point);
 * pointHas('x'); //=> true
 * pointHas('y'); //=> true
 * pointHas('z'); //=> false
 * ```
 */
export function has(__: Placeholder, obj: unknown): (s: string) => boolean;
export function has(__: Placeholder): <P extends string>(obj: unknown, s: P) => obj is ObjectHavingSome<P>;
export function has<P extends string>(s: P, obj: unknown): obj is ObjectHavingSome<P>;
export function has<P extends string>(s: P): (obj: unknown) => obj is ObjectHavingSome<P>;

/**
 * Returns whether or not an object or its prototype chain has a property with the specified name.
 *
 * @example
 * ```typescript
 * class Rectangle {
 *   constructor(public width: number, public height: number) {}
 *
 *   area() {
 *     return this.width * this.height;
 *   }
 * }
 *
 * const square = new Rectangle(2, 2);
 * R.hasIn('width', square); //=> true
 * R.hasIn('area', square);  //=> true
 * ```
 */
export function hasIn<T>(s: string, obj: T): boolean;
export function hasIn(s: string): <T>(obj: T) => boolean;

/**
 * Returns whether or not a path exists in an object. Only the object's own properties are checked.
 *
 * See also {@link has}.
 *
 * @example
 * ```typescript
 * R.hasPath(['a', 'b'], {a: {b: 2}});         // => true
 * R.hasPath(['a', 'b'], {a: {b: undefined}}); // => true
 * R.hasPath(['a', 'b'], {a: {c: 2}});         // => false
 * R.hasPath(['a', 'b'], {});                  // => false
 * ```
 */
export function hasPath<T>(list: readonly string[], obj: T): boolean;
export function hasPath(list: readonly string[]): <T>(obj: T) => boolean;

/**
 * Returns the first element in a list.
 * In some libraries this function is named `first`.
 *
 * See also {@link tail}, {@link init}, {@link last}.
 *
 * @example
 * ```typescript
 * R.head(['fi', 'fo', 'fum']); //=> 'fi'
 * R.head([]); //=> undefined
 *
 * R.head('abc'); //=> 'a'
 * R.head(''); //=> ''
 * ```
 */
export function head(str: string): string;
export function head(list: readonly []): undefined;
export function head<T>(list: readonly T[]): T | undefined;

/**
 * Returns `true` if its arguments are identical, `false` otherwise.
 * Values are identical if they reference the same memory.
 * `NaN` is identical to `NaN`; `0` and `-0` are not identical.
 *
 * @note This is merely a curried version of ES6 `Object.is`.
 *
 * @example
 * ```typescript
 * const o = {};
 * R.identical(o, o); //=> true
 * R.identical(1, 1); //=> true
 * R.identical<string | number>(1, '1'); //=> false
 * R.identical([], []); //=> false
 * R.identical(0, -0); //=> false
 * R.identical(NaN, NaN); //=> true
 * ```
 */
export function identical<T>(a: T, b: T): boolean;
export function identical<T>(a: T): (b: T) => boolean;

/**
 * A function that returns its argument.
 * Good as a default or placeholder function.
 *
 * @example
 * ```typescript
 * R.identity(1); //=> 1
 *
 * const obj = {};
 * R.identity(obj) === obj; //=> true
 * ```
 */
export function identity<T>(a: T): T;

/**
 * Creates a function that will process either the onTrue or the onFalse function depending upon the result
 * of the condition predicate.
 *
 * See also {@link unless}, {@link when}, {@link cond}.
 *
 * @example
 * ```typescript
 * const incCount = R.ifElse(
 *   R.has('count'),
 *   R.over(R.lensProp<{ count: number; }>('count'), R.inc),
 *   R.assoc('count', 1)
 * );
 * incCount({ count: 1 }); //=> { count: 2 }
 * ```
 */
export function ifElse<T, TF extends T, TOnTrueResult, TOnFalseResult>(
    pred: PredTypeguard<T, TF>,
    onTrue: (a: TF) => TOnTrueResult,
    onFalse: (a: Exclude<T, TF>) => TOnFalseResult,
): (a: T) => TOnTrueResult | TOnFalseResult;
export function ifElse<TArgs extends any[], TOnTrueResult, TOnFalseResult>(
    fn: Pred<TArgs>,
    onTrue: (...args: TArgs) => TOnTrueResult,
    onFalse: (...args: TArgs) => TOnFalseResult,
): (...args: TArgs) => TOnTrueResult | TOnFalseResult;

/**
 * Increments its argument.
 *
 * See also {@link dec}.
 *
 * @example
 * ```typescript
 * R.inc(42); //=> 43
 * ```
 */
export function inc(n: number): number;

/**
 * Returns `true` if the specified value is equal, in `R.equals` terms,
 * to at least one element of the given list; `false` otherwise.
 * Also works with strings.
 *
 * See also {@link any}.
 *
 * @example
 * ```typescript
 * R.includes(3, [1, 2, 3]);   //=> true
 * R.includes(4, [1, 2, 3]);   //=> false
 * R.includes([42], [[42]]);   //=> true
 * R.includes('ba', 'banana'); //=> true
 * R.includes({ name: 'Fred' }, [{ name: 'Fred' }]); //=> true
 * ```
 */
export function includes(__: Placeholder, list: readonly string[] | string): (s: string) => boolean;
export function includes<T>(__: Placeholder, list: readonly T[]): (target: T) => boolean;
export function includes(__: Placeholder): (list: readonly string[] | string, s: string) => boolean;
export function includes<T>(__: Placeholder): (list: readonly T[], target: T) => boolean;
export function includes(s: string, list: readonly string[] | string): boolean;
export function includes(s: string): (list: readonly string[] | string) => boolean;
export function includes<T>(target: T, list: readonly T[]): boolean;
export function includes<T>(target: T): (list: readonly T[]) => boolean;

/**
 * Given a function that generates a key,
 * turns a list of objects into an object indexing the objects by the given key.
 *
 * @note If multiple objects generate the same value for the indexing key
 * only the last value will be included in the generated object.
 *
 * Acts as a transducer if a transformer is given in list position.
 *
 * See also {@link groupBy}, {@link transduce}.
 *
 * @example
 * ```typescript
 * const list = [{id: 'xyz', title: 'A'}, {id: 'abc', title: 'B'}];
 * R.indexBy(R.prop('id'), list);
 * //=> {abc: {id: 'abc', title: 'B'}, xyz: {id: 'xyz', title: 'A'}}
 * ```
 */
export function indexBy<T, K extends string | number = string>(fn: (a: T) => K, list: readonly T[]): { [key in K]: T };
export function indexBy<T, K extends string | number | undefined = string>(
    fn: (a: T) => K,
    list: readonly T[],
): { [key in NonNullable<K>]?: T };
export function indexBy<T, K extends string | number = string>(
    fn: (a: T) => K,
): (list: readonly T[]) => { [key in K]: T };
export function indexBy<T, K extends string | number | undefined = string>(
    fn: (a: T) => K | undefined,
): (list: readonly T[]) => { [key in NonNullable<K>]?: T };

/**
 * Returns the position of the first occurrence of an item in an array,
 * or -1 if the item is not included in the array.
 * {@link equals `R.equals`} is used to determine equality.
 *
 * See also {@link lastIndexOf}, {@link findIndex}.
 *
 * @example
 * ```typescript
 * R.indexOf(3, [1,2,3,4]);  //=> 2
 * R.indexOf(10, [1,2,3,4]); //=> -1
 * ```
 */
export function indexOf(target: string, list: readonly string[] | string): number;
export function indexOf(target: string): (list: readonly string[] | string) => number;
export function indexOf<T>(target: T, list: readonly T[]): number;
export function indexOf<T>(target: T): (list: readonly T[]) => number;

/**
 * Returns all but the last element of the given list or string.
 *
 * See also {@link last}, {@link head}, {@link tail}.
 *
 * @example
 * ```typescript
 * R.init([1, 2, 3]); //=> [1, 2]
 * R.init([1, 2]);    //=> [1]
 * R.init([1]);       //=> []
 * R.init([]);        //=> []
 *
 * R.init('abc'); //=> 'ab'
 * R.init('ab');  //=> 'a'
 * R.init('a');   //=> ''
 * R.init('');    //=> ''
 * ```
 */
export function init<T>(list: readonly T[]): T[];
export function init(list: string): string;

/**
 * Takes a predicate `pred`, a list `xs`, and a list `ys`,
 * and returns a list `xs'` comprising each of the elements of `xs`
 * which is equal to one or more elements of `ys` according to `pred`.
 *
 * `pred` must be a binary function expecting an element from each list.
 *
 * `xs`, `ys`, and `xs'` are treated as sets, semantically, so ordering should not be significant,
 * but since `xs'` is ordered the implementation guarantees
 * that its values are in the same order as they appear in `xs`.
 * Duplicates are not removed, so `xs'` may contain duplicates if `xs` contains duplicates.
 *
 * See also {@link intersection}.
 *
 * @example
 * ```typescript
 * R.innerJoin(
 *   (record, id) => record.id === id,
 *   [{id: 824, name: 'Richie Furay'},
 *    {id: 956, name: 'Dewey Martin'},
 *    {id: 313, name: 'Bruce Palmer'},
 *    {id: 456, name: 'Stephen Stills'},
 *    {id: 177, name: 'Neil Young'}],
 *   [177, 456, 999]
 * );
 * //=> [{id: 456, name: 'Stephen Stills'}, {id: 177, name: 'Neil Young'}]
 * ```
 */
export function innerJoin<T1, T2>(pred: (a: T1, b: T2) => boolean, list1: readonly T1[], list2: readonly T2[]): T1[];
export function innerJoin<T1, T2>(
    pred: (a: T1, b: T2) => boolean,
): (list1: readonly T1[], list2: readonly T2[]) => T1[];
export function innerJoin<T1, T2>(
    pred: (a: T1, b: T2) => boolean,
    list1: readonly T1[],
): (list2: readonly T2[]) => T1[];

/**
 * Returns a copy of the list with the element inserted at the index.
 *
 * @example
 * ```typescript
 * R.insert<string | number>(2, 'x', [1,2,3,4]); //=> [1,2,'x',3,4]
 * ```
 */
export function insert<T>(index: number, elt: T, list: readonly T[]): T[];
export function insert<T>(index: number, elt: T): (list: readonly T[]) => T[];
export function insert(index: number): <T>(elt: T, list: readonly T[]) => T[];

/**
 * Returns a copy of the list with the elements inserted at the index.
 *
 * @example
 * ```typescript
 * R.insertAll<string | number>(2, ['x','y','z'], [1,2,3,4]); //=> [1,2,'x','y','z',3,4]
 * ```
 */
export function insertAll<T>(index: number, elts: readonly T[], list: readonly T[]): T[];
export function insertAll<T>(index: number, elts: readonly T[]): (list: readonly T[]) => T[];
export function insertAll(index: number): <T>(elts: readonly T[], list: readonly T[]) => T[];

/**
 * Combines two lists into a set (i.e. no duplicates) composed of those elements common to both lists.
 *
 * See also {@link innerJoin}.
 *
 * @example
 * ```typescript
 * R.intersection([1,2,3,4], [7,6,5,4,3]); //=> [4, 3]
 * ```
 */
export function intersection<T>(list1: readonly T[], list2: readonly T[]): T[];
export function intersection<T>(list1: readonly T[]): (list2: readonly T[]) => T[];

/**
 * Creates a new list with the separator interposed between elements.
 *
 * Dispatches to the `intersperse` method of the second argument, if present.
 *
 * @example
 * ```typescript
 * R.intersperse('a', ['b', 'n', 'n', 's']); //=> ['b', 'a', 'n', 'a', 'n', 'a', 's']
 * ```
 */
export function intersperse<T>(separator: T, list: readonly T[]): T[];
export function intersperse<T>(separator: T): (list: readonly T[]) => T[];

/**
 * Transforms the items of the list with the transducer
 * and appends the transformed items to the accumulator
 * using an appropriate iterator function based on the accumulator type.
 *
 * The accumulator can be an array, string, object or a transformer.
 * Iterated items will be appended to arrays and concatenated to strings.
 * Objects will be merged directly or 2-item tuples will be merged as key, value pairs.
 *
 * The accumulator can also be a transformer object that provides:
 * - A 2-arity iterator function, which is passed directly to reduce.
 * - A 0-arity initial value function, which is used to provide the initial accumulator.
 * - A 1-arity result extraction function, which is used to convert the final accumulator into the return type.
 * In most cases is it is {@link identity `R.identity`}.
 *
 * The iteration is performed with {@link reduce `R.reduce`} after initializing the transducer.
 *
 * See also {@link transduce}.
 *
 * @example
 * ```typescript
 * const numbers = [1, 2, 3, 4];
 * const transducer = R.compose(R.map(R.add(1)), R.take(2));
 *
 * R.into([], transducer, numbers); //=> [2, 3]
 *
 * const intoArray = R.into([]);
 * intoArray(transducer, numbers); //=> [2, 3]
 * ```
 */
export function into<T>(acc: any, xf: AnyFunction, list: readonly T[]): T[];
export function into<T, R>(acc: any, xf: (...args: any[]) => R[], list: readonly T[]): R[];
export function into(acc: any, xf: AnyFunction): <T>(list: readonly T[]) => T[];
export function into(acc: any): <T>(xf: AnyFunction, list: readonly T[]) => T[];

/**
 * Same as `R.invertObj`,
 * however this accounts for objects with duplicate values by putting the values into an array.
 *
 * See also {@link invertObj}.
 *
 * @example
 * ```typescript
 * const raceResultsByFirstName = {
 *   first: 'alice',
 *   second: 'jake',
 *   third: 'alice',
 * };
 * R.invert(raceResultsByFirstName);
 * //=> { 'alice': ['first', 'third'], 'jake': ['second'] }
 * ```
 */
export function invert<T>(obj: T): { [index: string]: string[] };

/**
 * Returns a new object with the keys of the given object as values, and the values of the given object as keys.
 *
 * @note If multiple objects generate the same value for the indexing key
 * only the last value will be included in the generated object.
 *
 * See also {@link invert}.
 *
 * @example
 * ```typescript
 * const raceResults = {
 *   first: 'alice',
 *   second: 'jake'
 * };
 * R.invertObj(raceResults);
 * //=> { 'alice': 'first', 'jake':'second' }
 *
 * // Alternatively:
 * const raceResults = ['alice', 'jake'];
 * R.invertObj(raceResults);
 * //=> { 'alice': '0', 'jake':'1' }
 * ```
 */
export function invertObj(obj: { [index: string]: string } | { [index: number]: string }): { [index: string]: string };

/**
 * Turns a named method with a specified arity into a function that can be called directly
 * supplied with arguments and a target object.
 *
 * The returned function is curried and accepts `arity + 1` parameters
 * where the final parameter is the target object.
 *
 * @example
 * ```typescript
 * const sliceFrom = R.invoker<(start: number, s: string) => string>(1, 'slice');
 * sliceFrom(6, 'abcdefghijklm'); //=> 'ghijklm'
 * const sliceFrom6 = R.invoker<(start: number, end: number, s: string) => string>(2, 'slice')(6);
 * sliceFrom6(8, 'abcdefghijklm'); //=> 'gh'
 *
 * const dog = {
 *   speak: async () => 'Woof!'
 * };
 * const speak = R.invoker<(speaker: { speak: () => Promise<string> }) => Promise<string>>(0, 'speak');
 * speak(dog).then(console.log) //~> 'Woof!'
 * ```
 */
export function invoker(arity: number, method: string): (...args: unknown[]) => any;

/**
 * See if an object (`val`) is an instance of the supplied constructor.
 * This function will check up the inheritance chain, if any.
 * If `val` was created using `Object.create`, `R.is(Object, val) === true`.
 *
 * See also {@link propIs}.
 */
export function is<C extends AnyFunction>(ctor: C, val: any): val is ReturnType<C>;
export function is<C extends AnyConstructor>(ctor: C, val: any): val is InstanceType<C>;
export function is<C extends AnyFunction>(ctor: C): (val: any) => val is ReturnType<C>;
export function is<C extends AnyConstructor>(ctor: C): (val: any) => val is InstanceType<C>;

/**
 * Returns `true` if the given value is its type's empty value; `false` otherwise.
 *
 * See also {@link empty}.
 *
 * @example
 * ```typescript
 * R.isEmpty([1, 2, 3]);           //=> false
 * R.isEmpty([]);                  //=> true
 * R.isEmpty('');                  //=> true
 * R.isEmpty(null);                //=> false
 * R.isEmpty({});                  //=> true
 * R.isEmpty({length: 0});         //=> false
 * R.isEmpty(Uint8Array.from([])); //=> true
 * ```
 */
export function isEmpty(value: any): boolean;

/**
 * Checks if the input value is `null` or `undefined`.
 *
 * @example
 * ```typescript
 * R.isNil(null); //=> true
 * R.isNil(undefined); //=> true
 * R.isNil(0); //=> false
 * R.isNil([]); //=> false
 * ```
 */
export function isNil(value: any): value is null | undefined;

/**
 * Returns a string made by inserting the given separator between each element
 * and concatenating all the elements into a single string.
 *
 * See also {@link split}.
 *
 * @example
 * ```typescript
 * const spacer = R.join(' ');
 * spacer(['a', 2, 3.4]);  //=> 'a 2 3.4'
 * R.join('|', [1, 2, 3]); //=> '1|2|3'
 * ```
 */
export function join(x: string, xs: readonly any[]): string;
export function join(x: string): (xs: readonly any[]) => string;

/**
 * Applies a list of functions to a list of values.
 *
 * See also {@link applySpec}.
 *
 * @example
 * ```typescript
 * const getRange = R.juxt([Math.min, Math.max]);
 * getRange(3, 4, 9, -3); //=> [-3, 9]
 * ```
 */
export function juxt<A extends any[], R1>(fns: [(...args: A) => R1]): (...args: A) => [R1];
export function juxt<A extends any[], R1, R2>(fns: [(...args: A) => R1, (...args: A) => R2]): (...args: A) => [R1, R2];
export function juxt<A extends any[], R1, R2, R3>(
    fns: [(...args: A) => R1, (...args: A) => R2, (...args: A) => R3],
): (...args: A) => [R1, R2, R3];
export function juxt<A extends any[], R1, R2, R3, R4>(
    fns: [(...args: A) => R1, (...args: A) => R2, (...args: A) => R3, (...args: A) => R4],
): (...args: A) => [R1, R2, R3, R4];
export function juxt<A extends any[], R1, R2, R3, R4, R5>(
    fns: [(...args: A) => R1, (...args: A) => R2, (...args: A) => R3, (...args: A) => R4, (...args: A) => R5],
): (...args: A) => [R1, R2, R3, R4, R5];
export function juxt<A extends any[], U>(fns: ReadonlyArray<(...args: A) => U>): (...args: A) => U[];

/**
 * Returns a list containing the names of all the enumerable own properties of the supplied object.
 *
 * @note The order of the output array is not guaranteed to be consistent across different JS platforms.
 *
 * See also {@link keysIn}, {@link values}, {@link toPairs}.
 *
 * @example
 * ```typescript
 * R.keys({a: 1, b: 2, c: 3}); //=> ['a', 'b', 'c']
 * ```
 */
export function keys<T extends object>(x: T): Array<keyof T>;
export function keys<T>(x: T): string[];

/**
 * Returns a list containing the names of all the properties of the supplied object,
 * including prototype properties.
 *
 * @note The order of the output array is not guaranteed to be consistent across different JS platforms.
 *
 * See also {@link keys}, {@link valuesIn}.
 *
 * @example
 * ```typescript
 * class F {
 *   y = 'Y';
 *   constructor(public x: string = 'X') {}
 * }
 *
 * const f = new F();
 * R.keysIn(f); //=> ['x', 'y']
 * ```
 */
export function keysIn<T>(obj: T): string[];

/**
 * Returns the last element of the given list or string.
 *
 * See also {@link init}, {@link head}, {@link tail}.
 *
 * @example
 * ```typescript
 * R.last(['fi', 'fo', 'fum']); //=> 'fum'
 * R.last([]);    //=> undefined
 *
 * R.last('abc'); //=> 'c'
 * R.last('');    //=> ''
 * ```
 */
export function last(str: string): string;
export function last(list: readonly []): undefined;
export function last<T>(list: readonly T[]): T | undefined;

/**
 * Returns the position of the last occurrence of an item in an array,
 * or `-1` if the item is not included in the array.
 * {@link equals `R.equals`} is used to determine equality.
 *
 * See also {@link indexOf}, {@link findLastIndex}.
 *
 * @example
 * ```typescript
 * R.lastIndexOf(3, [-1,3,3,0,1,2,3,4]); //=> 6
 * R.lastIndexOf(10, [1,2,3,4]); //=> -1
 * ```
 */
export function lastIndexOf(target: string, list: readonly string[] | string): number;
export function lastIndexOf(target: string): (list: readonly string[] | string) => number;
export function lastIndexOf<T>(target: T, list: readonly T[]): number;
export function lastIndexOf<T>(target: T): (list: readonly T[]) => number;

/**
 * Returns the number of elements in the array by returning `list.length`.
 *
 * @example
 * ```typescript
 * R.length([]); //=> 0
 * R.length([1, 2, 3]); //=> 3
 * ```
 */
export function length<T extends ArrayLike<unknown>>(list: T): number;

/**
 * Returns a lens for the given getter and setter functions.
 * The getter "gets" the value of the focus; the setter "sets" the value of the focus.
 * The setter should not mutate the data structure.
 *
 * See also {@link view}, {@link set}, {@link over}, {@link lensIndex}, {@link lensProp}.
 */
export function lens<S, A>(getter: (s: S) => A, setter: (a: A, s: S) => S): Lens<S, A>;

/**
 * Returns a lens whose focus is the specified index.
 *
 * See also {@link view}, {@link set}, {@link over}, {@link nth}, {@link lens}.
 *
 * @example
 * ```typescript
 * const headLens = R.lensIndex<string>(0);
 *
 * R.view(headLens, ['a', 'b', 'c']);            //=> 'a'
 * R.set(headLens, 'x', ['a', 'b', 'c']);        //=> ['x', 'b', 'c']
 * R.over(headLens, R.toUpper, ['a', 'b', 'c']); //=> ['A', 'b', 'c']
 * ```
 */
export function lensIndex<A>(n: number): Lens<A[], A>;
export function lensIndex<A extends any[], N extends number>(n: N): Lens<A, A[N]>;

/**
 * Returns a lens whose focus is the specified path.
 *
 * See also {@link view}, {@link set}, {@link over}, {@link lens}.
 *
 * @example
 * ```typescript
 * const xHeadYLens = R.lensPath<{ x: { y: number; z: number; }[]; }, 'x', 0, 'y'>(['x', 0, 'y']);
 *
 * R.view(xHeadYLens, {x: [{y: 2, z: 3}, {y: 4, z: 5}]});
 * //=> 2
 * R.set(xHeadYLens, 1, {x: [{y: 2, z: 3}, {y: 4, z: 5}]});
 * //=> {x: [{y: 1, z: 3}, {y: 4, z: 5}]}
 * R.over(xHeadYLens, R.negate, {x: [{y: 2, z: 3}, {y: 4, z: 5}]});
 * //=> {x: [{y: -2, z: 3}, {y: 4, z: 5}]}
 * ```
 */
export function lensPath<S, K0 extends keyof S = keyof S>(path: [K0]): Lens<S, S[K0]>;
export function lensPath<S, K0 extends keyof S = keyof S, K1 extends keyof S[K0] = keyof S[K0]>(
    path: [K0, K1],
): Lens<S, S[K0][K1]>;
export function lensPath<
    S,
    K0 extends keyof S = keyof S,
    K1 extends keyof S[K0] = keyof S[K0],
    K2 extends keyof S[K0][K1] = keyof S[K0][K1],
>(path: [K0, K1, K2]): Lens<S, S[K0][K1][K2]>;
export function lensPath<
    S,
    K0 extends keyof S = keyof S,
    K1 extends keyof S[K0] = keyof S[K0],
    K2 extends keyof S[K0][K1] = keyof S[K0][K1],
    K3 extends keyof S[K0][K1][K2] = keyof S[K0][K1][K2],
>(path: [K0, K1, K2, K3]): Lens<S, S[K0][K1][K2][K3]>;
export function lensPath<
    S,
    K0 extends keyof S = keyof S,
    K1 extends keyof S[K0] = keyof S[K0],
    K2 extends keyof S[K0][K1] = keyof S[K0][K1],
    K3 extends keyof S[K0][K1][K2] = keyof S[K0][K1][K2],
    K4 extends keyof S[K0][K1][K2][K3] = keyof S[K0][K1][K2][K3],
>(path: [K0, K1, K2, K3, K4]): Lens<S, S[K0][K1][K2][K3][K4]>;
export function lensPath<
    S,
    K0 extends keyof S = keyof S,
    K1 extends keyof S[K0] = keyof S[K0],
    K2 extends keyof S[K0][K1] = keyof S[K0][K1],
    K3 extends keyof S[K0][K1][K2] = keyof S[K0][K1][K2],
    K4 extends keyof S[K0][K1][K2][K3] = keyof S[K0][K1][K2][K3],
    K5 extends keyof S[K0][K1][K2][K3][K4] = keyof S[K0][K1][K2][K3][K4],
>(path: [K0, K1, K2, K3, K4, K5]): Lens<S, S[K0][K1][K2][K3][K4][K5]>;

export function lensPath<S = any, A = any>(path: Path): Lens<S, A>;

/**
 * Returns a lens whose focus is the specified property.
 *
 * See also {@link view}, {@link set}, {@link over}, {@link lens}.
 *
 * @example
 * ```typescript
 * type Point = { x: number; y: number; };
 *
 * const xLens = R.lensProp<Point, 'x'>('x');
 *
 * R.view(xLens, {x: 1, y: 2});           //=> 1
 * R.set(xLens, 4, {x: 1, y: 2});         //=> {x: 4, y: 2}
 * R.over(xLens, R.negate, {x: 1, y: 2}); //=> {x: -1, y: 2}
 * ```
 */
export function lensProp<S, K extends keyof S = keyof S>(prop: K): Lens<S, S[K]>;

/**
 * "lifts" a function of arity > 1 so that it may "map over" a list,
 * `Function` or other object that satisfies the FantasyLand Apply spec.
 *
 * See also {@link liftN}.
 *
 * @example
 * ```typescript
 * const madd3 = R.lift((a: number, b: number, c: number) => a + b + c);
 *
 * madd3([100, 200], [30, 40], [5, 6, 7]); //=> [135, 136, 137, 145, 146, 147, 235, 236, 237, 245, 246, 247]
 *
 * const madd5 = R.lift((a: number, b: number, c: number, d: number, e: number) => a + b + c + d + e);
 *
 * madd5([10, 20], [1], [2, 3], [4], [100, 200]); //=> [117, 217, 118, 218, 127, 227, 128, 228]
 * ```
 */
export function lift<F extends AnyFunction>(
    fn: F,
): {
    (...args: ToTupleOfArray<Parameters<F>>): Array<ReturnType<F>>;
    <R>(...args: ToTupleOfFunction<R, Parameters<F>>): (arg: R) => ReturnType<F>;
};

/**
 * "lifts" a function to be the specified arity,
 * so that it may "map over" that many lists, Functions or other objects
 * that satisfy the FantasyLand Apply spec.
 *
 * See also {@link lift}, {@link ap}.
 *
 * @example
 * ```typescript
 * const madd3 = R.liftN(3, (...args: [number, number, number]) => R.sum(args));
 * madd3([1,2,3], [1,2,3], [1]); //=> [3, 4, 5, 4, 5, 6, 5, 6, 7]
 * ```
 */
export function liftN<N extends number, F extends AnyFunction>(
    n: N,
    fn: F,
): {
    (...args: Take<N, ToTupleOfArray<Parameters<F>>>): Array<ReturnType<F>>;
    <R>(...args: Take<N, ToTupleOfFunction<R, Parameters<F>>>): (arg: R) => ReturnType<F>;
};

/**
 * Returns `true` if the first parameter is less than the second; `false` otherwise.
 *
 * See also {@link gt}, {@link gte}, {@link lte}.
 *
 * @example
 * ```typescript
 * R.lt(2, 1); //=> false
 * R.lt(2, 2); //=> false
 * R.lt(2, 3); //=> true
 * R.lt('a', 'z'); //=> true
 * R.lt('z', 'a'); //=> false
 * ```
 */
export function lt(__: Placeholder, b: number): (a: number) => boolean;
export function lt(__: Placeholder): (b: number, a: number) => boolean;
export function lt(a: number, b: number): boolean;
export function lt(a: string, b: string): boolean;
export function lt(a: number): (b: number) => boolean;

/**
 * Returns `true` if the first parameter is less than or equal to the second; `false` otherwise.
 *
 * See also {@link gt}, {@link gte}, {@link lt}.
 *
 * @example
 * ```typescript
 * R.lte(2, 1); //=> false
 * R.lte(2, 2); //=> true
 * R.lte(2, 3); //=> true
 * R.lte('a', 'z'); //=> true
 * R.lte('z', 'a'); //=> false
 * ```
 */
export function lte(__: Placeholder, b: number): (a: number) => boolean;
export function lte(__: Placeholder): (b: number, a: number) => boolean;
export function lte(a: number, b: number): boolean;
export function lte(a: string, b: string): boolean;
export function lte(a: number): (b: number) => boolean;

/**
 * Takes a function and a functor,
 * applies the function to each of the functor's values,
 * and returns a functor of the same shape.
 *
 * Ramda provides suitable `map` implementations for `Array` and `Object`,
 * so this function may be applied to `[1, 2, 3]` or `{x: 1, y: 2, z: 3}`.
 *
 * Dispatches to the `map` method of the second argument, if present.
 *
 * Acts as a transducer if a transformer is given in list position.
 *
 * Also treats functions as functors and will compose them together.
 *
 * See also {@link addIndex}, {@link pluck}, {@link project}, {@link transduce}.
 *
 * @example
 * ```typescript
 * const double = x => x * 2;
 *
 * R.map(double, [1, 2, 3]); //=> [2, 4, 6]
 *
 * R.map(double, {x: 1, y: 2, z: 3}); //=> {x: 2, y: 4, z: 6}
 * ```
 */
export function map<T, U>(fn: (x: T) => U, list: readonly T[]): U[];
export function map<T, U>(fn: (x: T) => U): (list: readonly T[]) => U[];
export function map<T, U>(fn: (x: T[keyof T & keyof U] | ValueOfUnion<T>) => U[keyof T & keyof U], list: T): U;
export function map<T, U>(fn: (x: T[keyof T & keyof U] | ValueOfUnion<T>) => U[keyof T & keyof U]): (list: T) => U;
export function map<T, U>(fn: (x: T) => U, obj: Functor<T>): Functor<U>; // used in functors
export function map<T, U>(fn: (x: T) => U): (obj: Functor<T>) => Functor<U>; // used in functors

/**
 * The `mapAccum` function behaves like a combination of map and reduce;
 * it applies a function to each element of a list,
 * passing an accumulating parameter from left to right,
 * and returning a final value of this accumulator together with the new list.
 *
 * The iterator function receives two arguments, `acc` and `value`,
 * and should return a tuple `[acc, value]`.
 *
 * See also {@link scan}, {@link addIndex}, {@link mapAccumRight}.
 *
 * @example
 * ```typescript
 * const digits = ['1', '2', '3', '4'];
 * const appender = (a: string, b: string) => [a + b, a + b] as const;
 *
 * R.mapAccum(appender, '0', digits); //=> ['01234', ['01', '012', '0123', '01234']]
 * ```
 */
export function mapAccum<T, U, TResult>(
    fn: (acc: U, value: T) => [U, TResult],
    acc: U,
    list: readonly T[],
): [U, TResult[]];
export function mapAccum<T, U, TResult>(
    fn: (acc: U, value: T) => [U, TResult],
): (acc: U, list: readonly T[]) => [U, TResult[]];
export function mapAccum<T, U, TResult>(
    fn: (acc: U, value: T) => [U, TResult],
    acc: U,
): (list: readonly T[]) => [U, TResult[]];

/**
 * Applies a function to each element of a list,
 * passing an accumulating parameter from right to left,
 * and returning a final value of this accumulator together with the new list.
 *
 * Similar to `R.mapAccum`, except moves through the input list from the right to the left.
 *
 * The iterator function receives two arguments, `acc` and `value`,
 * and should return a tuple `[acc, value]`.
 *
 * See also {@link addIndex}, {@link mapAccum}.
 *
 * @example
 * ```typescript
 * const digits = ['1', '2', '3', '4'];
 * const appender = (a: string, b: string) => [b + a, b + a] as const;
 *
 * R.mapAccumRight(appender, '5', digits); //=> ['12345', ['12345', '2345', '345', '45']]
 * ```
 */
export function mapAccumRight<T, U, TResult>(
    fn: (acc: U, value: T) => [U, TResult],
    acc: U,
    list: readonly T[],
): [U, TResult[]];
export function mapAccumRight<T, U, TResult>(
    fn: (acc: U, value: T) => [U, TResult],
): (acc: U, list: readonly T[]) => [U, TResult[]];
export function mapAccumRight<T, U, TResult>(
    fn: (acc: U, value: T) => [U, TResult],
    acc: U,
): (list: readonly T[]) => [U, TResult[]];

/**
 * Like mapObj, but but passes additional arguments to the predicate function.
 */
type PartialRecord<K extends keyof any, T> = {
    [P in K]?: T;
};
export function mapObjIndexed<T, TResult, TKey extends string>(
    fn: (value: T, key: TKey, obj?: Record<TKey, T>) => TResult,
    obj: Record<TKey, T>,
): Record<TKey, TResult>;
export function mapObjIndexed<T, TResult, TKey extends string>(
    fn: (value: T, key: TKey, obj?: Record<TKey, T>) => TResult,
    obj: PartialRecord<TKey, T>,
): PartialRecord<TKey, TResult>;
export function mapObjIndexed<T, TResult, TKey extends string>(
    fn: (value: T, key: TKey, obj?: Record<TKey, T>) => TResult,
): (obj: Record<TKey, T>) => Record<TKey, TResult>;
export function mapObjIndexed<T, TResult, TKey extends string>(
    fn: (value: T, key: TKey, obj?: PartialRecord<TKey, T>) => TResult,
): (obj: Record<TKey, T>) => PartialRecord<TKey, TResult>;
export function mapObjIndexed<T, TResult>(
    fn: (
        value: T,
        key: string,
        obj?: {
            [key: string]: T;
        },
    ) => TResult,
    obj: {
        [key: string]: T;
    },
): {
    [key: string]: TResult;
};

/**
 * Tests a `RegExp` against a String.
 *
 * @note This function will return an empty array when there are no matches.
 * This differs from `String.prototype.match` which returns `null` when there are no matches.
 *
 * @example
 * ```typescript
 * R.match(/([a-z]a)/g, 'bananas'); //=> ['ba', 'na', 'na']
 * R.match(/a/, 'b'); //=> []
 * ```
 */
export function match(regexp: RegExp, str: string): string[];
export function match(regexp: RegExp): (str: string) => string[];

/**
 * `mathMod` behaves like the modulo operator should mathematically,
 * unlike the `%` operator (and by extension, `R.modulo`).
 * So while `-17 % 5` is `-2`, `mathMod(-17, 5)` is `3`.
 * `mathMod` requires integer arguments,
 * and returns `NaN` when the modulus is zero or negative.
 *
 * See also {@link modulo}.
 *
 * @example
 * ```typescript
 * R.mathMod(-17, 5);  //=> 3
 * R.mathMod(17, 5);   //=> 2
 * R.mathMod(17, -5);  //=> NaN
 * R.mathMod(17, 0);   //=> NaN
 * R.mathMod(17.2, 5); //=> NaN
 * R.mathMod(17, 5.3); //=> NaN
 *
 * const clock = R.mathMod(R.__, 12);
 * clock(15); //=> 3
 * clock(24); //=> 0
 *
 * const seventeenMod = R.mathMod(17);
 * seventeenMod(3);  //=> 2
 * seventeenMod(4);  //=> 1
 * seventeenMod(10); //=> 7
 * ```
 */
export function mathMod(__: Placeholder, b: number): (a: number) => number;
export function mathMod(__: Placeholder): (b: number, a: number) => number;
export function mathMod(a: number, b: number): number;
export function mathMod(a: number): (b: number) => number;

/**
 * Returns the larger of its two arguments.
 *
 * See also {@link maxBy}, {@link min}, {@link minBy}.
 *
 * @example
 * ```typescript
 * R.max(789, 123); //=> 789
 * R.max('a', 'b'); //=> 'b'
 * ```
 */
export function max<T extends Ord>(a: T, b: T): T;
export function max<T extends Ord>(a: T): (b: T) => T;

/**
 * Takes a function and two values, and returns whichever value produces
 * the larger result when passed to the provided function.
 *
 * See also {@link max}, {@link min}, {@link minBy}.
 *
 * @example
 * ```typescript
 * //  square :: Number -> Number
 * const square = (n: number) => n * n;
 *
 * R.maxBy(square, -3, 2); //=> -3
 *
 * R.reduce(R.maxBy(square), 0, [3, -5, 4, 1, -2]); //=> -5
 * R.reduce(R.maxBy(square), 0, [] as number[]); //=> 0
 * ```
 */
export function maxBy<T>(keyFn: (a: T) => Ord, a: T, b: T): T;
export function maxBy<T>(keyFn: (a: T) => Ord, a: T): (b: T) => T;
export function maxBy<T>(keyFn: (a: T) => Ord): _.F.Curry<(a: T, b: T) => T>;

/**
 * Returns the mean of the given list of numbers.
 *
 * See also {@link median}.
 *
 * @example
 * ```typescript
 * R.mean([2, 7, 9]); //=> 6
 * R.mean([]); //=> NaN
 * ```
 */
export function mean(list: readonly number[]): number;

/**
 * Returns the median of the given list of numbers.
 *
 * See also {@link mean}.
 *
 * @example
 * ```typescript
 * R.median([2, 9, 7]); //=> 7
 * R.median([7, 2, 10, 9]); //=> 8
 * R.median([]); //=> NaN
 * ```
 */
export function median(list: readonly number[]): number;

/**
 * Creates a new function that, when invoked,
 * caches the result of calling the given function for a given argument set and returns the result.
 * Subsequent calls to the memoized function with the same argument set will return the cached result.
 *
 * @example
 * ```typescript
 * let count = 0;
 * const factorial = R.memoizeWith(String, (n: number) => {
 *   count += 1;
 *   return R.product(R.range(1, n + 1));
 * });
 * factorial(5); //=> 120
 * factorial(5); //=> 120
 * factorial(5); //=> 120
 * count; //=> 1
 * ```
 */
export function memoizeWith<T extends AnyFunction>(keyFn: (...v: Parameters<T>) => string, fn: T): T;

/**
 * Creates one new object with the own properties from a list of objects.
 * If a key exists in more than one object,
 * the value from the last object it exists in will be used.
 *
 * See also {@link reduce}.
 *
 * @example
 * ```typescript
 * R.mergeAll([{foo:1},{bar:2},{baz:3}]); //=> {foo:1,bar:2,baz:3}
 * R.mergeAll([{foo:1},{foo:2},{bar:2}]); //=> {foo:2,bar:2}
 * ```
 */
export function mergeAll<Os extends readonly object[]>(list: Os): MergeAll<Os>;

/**
 * Creates a new object with the own properties of the first object
 * merged with the own properties of the second object.
 *
 * If a key exists in both objects:
 * - and both values are objects, the two values will be recursively merged
 * - otherwise the value from the first object will be used.
 *
 * See also {@link mergeDeepRight}, {@link mergeDeepWith}, {@link mergeDeepWithKey}.
 *
 * @example
 * ```typescript
 * R.mergeDeepLeft({ name: 'fred', age: 10, contact: { email: 'moo@example.com' }},
 *                 { age: 40, contact: { email: 'baa@example.com' }});
 * //=> { name: 'fred', age: 10, contact: { email: 'moo@example.com' }}
 * ```
 */
export function mergeDeepLeft<O1 extends object, O2 extends object>(o1: O1, o2: O2): Merge<O1, O2, 'deep'>;
export function mergeDeepLeft<O1 extends object>(o1: O1): <O2 extends object>(o2: O2) => Merge<O1, O2, 'deep'>;

/**
 * Creates a new object with the own properties of the first object
 * merged with the own properties of the second object.
 *
 * If a key exists in both objects:
 * - and both values are objects, the two values will be recursively merged
 * - otherwise the value from the second object will be used.
 *
 * See also {@link mergeDeepLeft}, {@link mergeDeepWith}, {@link mergeDeepWithKey}.
 *
 * @example
 * ```typescript
 * R.mergeDeepRight({ name: 'fred', age: 10, contact: { email: 'moo@example.com' }},
 *                  { age: 40, contact: { email: 'baa@example.com' }});
 * //=> { name: 'fred', age: 40, contact: { email: 'baa@example.com' }}
 * ```
 */
export function mergeDeepRight<O1 extends object, O2 extends object>(o1: O1, o2: O2): Merge<O2, O1, 'deep'>;
export function mergeDeepRight<O1 extends object>(a: O1): <O2 extends object>(o2: O2) => Merge<O2, O1, 'deep'>;

/**
 * Creates a new object with the own properties of the two provided objects.
 *
 * If a key exists in both objects:
 * - and both associated values are also objects then the values will be recursively merged.
 * - otherwise the provided function is applied to associated values
 * using the resulting value as the new value associated with the key.
 * If a key only exists in one object,
 * the value will be associated with the key of the resulting object.
 *
 * See also {@link mergeWith}, {@link mergeDeepWithKey}.
 *
 * @example
 * ```typescript
 * R.mergeDeepWith(R.concat,
 *                 { a: true, c: { values: [10, 20] }},
 *                 { b: true, c: { values: [15, 35] }});
 * //=> { a: true, b: true, c: { values: [10, 20, 15, 35] }}
 * ```
 */
export function mergeDeepWith<T1, T2>(fn: (x: any, z: any) => any, a: T1, b: T2): any;
export function mergeDeepWith<T1, T2>(fn: (x: any, z: any) => any, a: T1): (b: T2) => any;
export function mergeDeepWith<T1, T2>(fn: (x: any, z: any) => any): (a: T1, b: T2) => any;

/**
 * Creates a new object with the own properties of the two provided objects. If a key exists in both objects:
 * and both associated values are also objects then the values will be recursively merged.
 * otherwise the provided function is applied to the key and associated values using the resulting value as
 * the new value associated with the key. If a key only exists in one object, the value will be associated with
 * the key of the resulting object.
 *
 * See also {@link mergeWith}, {@link mergeWithKey}, {@link mergeDeepWith}.
 *
 * @example
 * ```typescript
 * let concatValues = <T>(k: string, l: T, r: T) => k == 'values' ? R.concat(l, r) : r
 * R.mergeDeepWithKey(concatValues,
 *                    { a: true, c: { thing: 'foo', values: [10, 20] }},
 *                    { b: true, c: { thing: 'bar', values: [15, 35] }});
 * //=> { a: true, b: true, c: { thing: 'bar', values: [10, 20, 15, 35] }}
 * ```
 */
export function mergeDeepWithKey<T1, T2>(fn: (k: string, x: any, z: any) => any, a: T1, b: T2): any;
export function mergeDeepWithKey<T1, T2>(fn: (k: string, x: any, z: any) => any, a: T1): (b: T2) => any;
export function mergeDeepWithKey<T1, T2>(fn: (k: string, x: any, z: any) => any): (a: T1, b: T2) => any;

/**
 * Create a new object with the own properties of the first object
 * merged with the own properties of the second object.
 * If a key exists in both objects,
 * the value from the first object will be used.
 *
 * See also {@link mergeRight}, {@link mergeDeepLeft}, {@link mergeWith}, {@link mergeWithKey}.
 *
 * @example
 * ```typescript
 * R.mergeLeft({ 'age': 40 }, { 'name': 'fred', 'age': 10 });
 * //=> { 'name': 'fred', 'age': 40 }
 *
 * const resetToDefault = R.mergeLeft({x: 0});
 * resetToDefault({x: 5, y: 2}); //=> {x: 0, y: 2}
 * ```
 */
export function mergeLeft<O1 extends object, O2 extends object>(a: O1, b: O2): Merge<O1, O2, 'flat'>;
export function mergeLeft<O1 extends object>(a: O1): <O2 extends object>(b: O2) => Merge<O1, O2, 'flat'>;

/**
 * Create a new object with the own properties of the first object merged with the own properties of the second object.
 * If a key exists in both objects, the value from the second object will be used.
 *
 * See also {@link mergeLeft}, {@link mergeDeepRight}, {@link mergeWith}, {@link mergeWithKey}.
 *
 * @example
 * ```typescript
 * R.mergeRight({ 'name': 'fred', 'age': 10 }, { 'age': 40 });
 * //=> { 'name': 'fred', 'age': 40 }
 *
 * const withDefaults = R.mergeRight({x: 0, y: 0});
 * withDefaults({y: 2}); //=> {x: 0, y: 2}
 * ```
 */
export function mergeRight<O1 extends object, O2 extends object>(a: O1, b: O2): Merge<O2, O1, 'flat'>;
export function mergeRight<O1 extends object>(a: O1): <O2 extends object>(b: O2) => Merge<O2, O1, 'flat'>;

/**
 * Creates a new object with the own properties of the two provided objects.
 * If a key exists in both objects,
 * the provided function is applied to the values associated with the key in each object,
 * with the result being used as the value associated with the key in the returned object.
 * The key will be excluded from the returned object
 * if the resulting value is `undefined`.
 *
 * See also {@link mergeDeepWith}, {@link merge}, {@link mergeWithKey}.
 *
 * @example
 * ```typescript
 * R.mergeWith(R.concat,
 *             { a: true, values: [10, 20] },
 *             { b: true, values: [15, 35] });
 * //=> { a: true, b: true, values: [10, 20, 15, 35] }
 * ```
 */
export function mergeWith<U, V>(fn: (x: any, z: any) => any, a: U, b: V): any;
export function mergeWith<U>(fn: (x: any, z: any) => any, a: U): <V>(b: V) => any;
export function mergeWith(fn: (x: any, z: any) => any): <U, V>(a: U, b: V) => any;

/**
 * Creates a new object with the own properties of the two provided objects.
 * If a key exists in both objects,
 * the provided function is applied to the key and the values associated with the key in each object,
 * with the result being used as the value associated with the key in the returned object.
 * The key will be excluded from the returned object
 * if the resulting value is `undefined`.
 *
 * See also {@link mergeDeepWithKey}, {@link merge}, {@link mergeWith}.
 *
 * @example
 * ```typescript
 * let concatValues = <T>(k: string, l: T, r: T) => k == 'values' ? R.concat(l as any, r as any) : r
 * R.mergeWithKey(concatValues,
 *                { a: true, thing: 'foo', values: [10, 20] },
 *                { b: true, thing: 'bar', values: [15, 35] });
 * //=> { a: true, b: true, thing: 'bar', values: [10, 20, 15, 35] }
 * ```
 */
export function mergeWithKey<U, V>(fn: (str: string, x: any, z: any) => any, a: U, b: V): any;
export function mergeWithKey<U>(fn: (str: string, x: any, z: any) => any, a: U): <V>(b: V) => any;
export function mergeWithKey(fn: (str: string, x: any, z: any) => any): <U, V>(a: U, b: V) => any;

/**
 * Returns the smaller of its two arguments.
 *
 * See also {@link minBy}, {@link max}.
 *
 * @example
 * ```typescript
 * R.min(789, 123); //=> 123
 * R.min('a', 'b'); //=> 'a'
 * ```
 */
export function min<T extends Ord>(a: T, b: T): T;
export function min<T extends Ord>(a: T): (b: T) => T;

/**
 * Takes a function and two values,
 * and returns whichever value produces the smaller result
 * when passed to the provided function.
 *
 * See also {@link min}, {@link maxBy}.
 *
 * @example
 * ```typescript
 * //  square :: Number -> Number
 * const square = (n: number) => n * n;
 *
 * R.minBy(square, -3, 2); //=> 2
 *
 * R.reduce(R.minBy(square), Infinity, [3, -5, 4, 1, -2]); //=> 1
 * R.reduce(R.minBy(square), Infinity, [] as number); //=> Infinity
 * ```
 */
export function minBy<T>(keyFn: (a: T) => Ord, a: T, b: T): T;
export function minBy<T>(keyFn: (a: T) => Ord, a: T): (b: T) => T;
export function minBy<T>(keyFn: (a: T) => Ord): _.F.Curry<(a: T, b: T) => T>;

/**
 * Returns the modulo of two numbers. Equivalent to `a % b` but curried.
 *
 * Divides the first parameter by the second and returns the remainder.
 * Note that this function preserves the JavaScript-style behavior for modulo.
 * For mathematical modulo see `R.mathMod`.
 *
 * See also {@link mathMod}.
 *
 * @example
 * ```typescript
 * R.modulo(17, 3); //=> 2
 * // JS behavior:
 * R.modulo(-17, 3); //=> -2
 * R.modulo(17, -3); //=> 2
 *
 * const isOdd = R.modulo(R.__, 2);
 * isOdd(42); //=> 0
 * isOdd(21); //=> 1
 * ```
 */
export function modulo(__: Placeholder, b: number): (a: number) => number;
export function modulo(__: Placeholder): (b: number, a: number) => number;
export function modulo(a: number, b: number): number;
export function modulo(a: number): (b: number) => number;

/**
 * Returns a copy of the given list
 * with the item at the given source index moved to the given destination index.
 *
 * @example
 * ```typescript
 * R.move(0, 2, ['a', 'b', 'c', 'd', 'e', 'f']); //=> ['b', 'c', 'a', 'd', 'e', 'f']
 * R.move(-1, 0, ['a', 'b', 'c', 'd', 'e', 'f']); //=> ['f', 'a', 'b', 'c', 'd', 'e'] list rotation
 * ```
 */
export function move<T>(from: number, to: number, list: readonly T[]): T[];
export function move(from: number, to: number): <T>(list: readonly T[]) => T[];
export function move(from: number): {
    <T>(to: number, list: readonly T[]): T[];
    (to: number): <T>(list: readonly T[]) => T[];
};

/**
 * Multiplies two numbers. Equivalent to `a * b` but curried.
 *
 * See also {@link divide}.
 *
 * @example
 * ```typescript
 * const double = R.multiply(2);
 * const triple = R.multiply(3);
 * double(3);        //=>  6
 * triple(4);        //=> 12
 * R.multiply(2, 5); //=> 10
 * ```
 */
export function multiply(a: number, b: number): number;
export function multiply(a: number): (b: number) => number;

/**
 * Wraps a function of any arity (including nullary) in a function that accepts exactly n parameters.
 * Any extraneous parameters will not be passed to the supplied function.
 *
 * See also {@link binary}, {@link unary}.
 *
 * @example
 * ```typescript
 * const takesTwoArgs = <T, U>(a: T, b: U) => [a, b];
 *
 * takesTwoArgs.length; //=> 2
 * takesTwoArgs(1, 2); //=> [1, 2]
 *
 * const takesOneArg = R.nAry(1, takesTwoArgs);
 * takesOneArg.length; //=> 1
 * // Only `n` arguments are passed to the wrapped function
 * takesOneArg(1); //=> [1, undefined]
 * ```
 */
export function nAry<N extends number, T extends AnyFunction>(
    n: N,
    fn: T,
): (...arg: _.T.Take<Parameters<T>, _.N.NumberOf<N>>) => ReturnType<T>;
export function nAry<N extends number>(
    n: N,
): <T extends AnyFunction>(fn: T) => (...arg: _.T.Take<Parameters<T>, _.N.NumberOf<N>>) => ReturnType<T>;

/**
 * Negates its argument.
 *
 * @example
 * ```typescript
 * R.negate(42); //=> -42
 * ```
 */
export function negate(n: number): number;

/**
 * Returns `true` if no elements of the list match the predicate, `false` otherwise.
 *
 * Dispatches to the `all` method of the second argument, if present.
 *
 * Acts as a transducer if a transformer is given in list position.
 *
 * See also {@link all}, {@link any}, {@link transduce}.
 *
 * @example
 * ```typescript
 * const isEven = (n: number) => n % 2 === 0;
 * const isOdd = (n: number) => n % 2 !== 0;
 *
 * R.none(isEven, [1, 3, 5, 7, 9, 11]); //=> true
 * R.none(isOdd, [1, 3, 5, 7, 8, 11]); //=> false
 * ```
 */
export function none<T>(fn: (a: T) => boolean, list: readonly T[]): boolean;
export function none<T>(fn: (a: T) => boolean): (list: readonly T[]) => boolean;

/**
 * A function that returns the `!` of its argument.
 * It will return true when passed falsy value, and false when passed a truthy one.
 *
 * See also {@link complement}.
 *
 * @example
 * ```typescript
 * R.not(true); //=> false
 * R.not(false); //=> true
 * R.not(0); //=> true
 * R.not(1); //=> false
 * ```
 */
export function not(value: any): boolean;

/**
 * Returns the nth element of the given list or string.
 *
 * If `n` is negative the element at index `length + n` is returned.
 *
 * @example
 * ```typescript
 * const list = ['foo', 'bar', 'baz', 'quux'];
 * R.nth(1, list); //=> 'bar'
 * R.nth(-1, list); //=> 'quux'
 * R.nth(-99, list); //=> undefined
 *
 * R.nth(2, 'abc'); //=> 'c'
 * R.nth(3, 'abc'); //=> ''
 * ```
 */
export function nth<T>(n: number, list: readonly T[]): T | undefined;
export function nth(n: number, list: string): string;
export function nth(
    n: number,
): <T extends readonly any[] | string>(list: T) => (T extends Array<infer E> ? E : string) | undefined;

/**
 * Returns a function which returns its nth argument.
 *
 * @example
 * ```typescript
 * R.nthArg(1)('a', 'b', 'c');  //=> 'b'
 * R.nthArg(-1)('a', 'b', 'c'); //=> 'c'
 * ```
 */
export function nthArg(n: number): (...args: unknown[]) => unknown;

/**
 * `o` is a curried composition function that returns a unary function.
 * Like `compose`, `o` performs right-to-left function composition.
 * Unlike `compose`, the rightmost function passed to `o` will be invoked with only one argument.
 * Also, unlike compose, `o` is limited to accepting only 2 unary functions.
 * The name `o` was chosen because of its similarity to the mathematical composition operator `∘`.
 *
 * See also {@link compose}, {@link pipe}.
 *
 * @example
 * ```typescript
 * type Name = { first: string; last: string; };
 *
 * const classyGreeting = (name: Name) => "The name's " + name.last + ", " + name.first + " " + name.last
 * const yellGreeting = R.o(R.toUpper, classyGreeting);
 * yellGreeting({first: 'James', last: 'Bond'}); //=> "THE NAME'S BOND, JAMES BOND"
 *
 * R.o(R.multiply(10), R.add(10))(-4) //=> 60
 * ```
 */
export function o<T1, T2, R>(f: (x: T2) => R, g: (x: T1) => T2, v: T1): R;
export function o<T1, T2, R>(f: (x: T2) => R, g: (x: T1) => T2): (v: T1) => R;
export function o<T2, R>(
    f: (x: T2) => R,
): {
    <T1>(g: (x: T1) => T2, v: T1): R;
    <T1>(g: (x: T1) => T2): (v: T1) => R;
};

/**
 * Creates an object containing a single key:value pair.
 *
 * See also {@link pair}.
 *
 * @example
 * ```typescript
 * const matchPhrases = R.compose(
 *   R.objOf('must'),
 *   R.map(R.objOf('match_phrase'))
 * );
 * matchPhrases(['foo', 'bar', 'baz']); //=> {must: [{match_phrase: 'foo'}, {match_phrase: 'bar'}, {match_phrase: 'baz'}]}
 * ```
 */
export function objOf<T, K extends string>(key: K, value: T): Record<K, T>;
export function objOf<K extends string>(key: K): <T>(value: T) => Record<K, T>;

/**
 * Returns a singleton array containing the value provided.
 *
 * @note This `of` is different from the ES6 `Array.of`.
 *
 * @example
 * ```typescript
 * R.of(null); //=> [null]
 * R.of([42]); //=> [[42]]
 * ```
 */
export function of<T>(x: T): T[];

/**
 * Returns a partial copy of an object omitting the keys specified.
 *
 * See also {@link pick}.
 *
 * @example
 * ```typescript
 * R.omit(['a', 'd'], {a: 1, b: 2, c: 3, d: 4}); //=> {b: 2, c: 3}
 * ```
 */
export function omit<T, K extends string>(names: readonly K[], obj: T): Omit<T, K>;
export function omit<K extends string>(names: readonly K[]): <T>(obj: T) => Omit<T, K>;

/**
 * Takes a binary function `f`, a unary function `g`, and two values.
 * Applies `g` to each value, then applies the result of each to `f`.
 * Also known as the P combinator.
 *
 * @example
 * ```typescript
 * const eqBy = R.on((a, b) => a === b);
 * eqBy(R.prop('a'), {b:0, a:1}, {a:1}) //=> true;
 *
 * const containsInsensitive = R.on(R.contains, R.toLower);
 * containsInsensitive('o', 'FOO'); //=> true
 * ```
 */
export function on<T, U, R>(combine: (a: U, b: U) => R, transform: (value: T) => U, a: T, b: T): R;
export function on<T, U, R>(combine: (a: U, b: U) => R, transform: (value: T) => U, a: T): (b: T) => R;
export function on<T, U, R>(
    combine: (a: U, b: U) => R,
    transform: (value: T) => U,
): {
    (a: T, b: T): R;
    (a: T): (b: T) => R;
};
export function on<U, R>(
    combine: (a: U, b: U) => R,
): {
    <T>(transform: (value: T) => U, a: T, b: T): R;
    <T>(transform: (value: T) => U, a: T): (b: T) => R;
    <T>(transform: (value: T) => U): {
        (a: T, b: T): R;
        (a: T): (b: T) => R;
    };
};
// For manually specifying overloads
export function on<T, U, R>(
    combine: (a: U, b: U) => R,
): {
    (transform: (value: T) => U, a: T, b: T): R;
    (transform: (value: T) => U, a: T): (b: T) => R;
    (transform: (value: T) => U): {
        (a: T, b: T): R;
        (a: T): (b: T) => R;
    };
};

/**
 * Accepts a function `fn` and returns a function that guards invocation of `fn`
 * such that `fn` can only ever be called once,
 * no matter how many times the returned function is invoked.
 * The first value calculated is returned in subsequent invocations.
 *
 * @example
 * ```typescript
 * const addOneOnce = R.once((x: number) => x + 1);
 * addOneOnce(10); //=> 11
 * addOneOnce(addOneOnce(50)); //=> 11
 * ```
 */
export function once<F extends AnyFunction>(fn: F): F;

/**
 * Returns the first argument if it is truthy, otherwise the second argument.
 *
 * Acts as boolean `or` if both inputs are booleans.
 *
 * @note This is **not** short-circuited, meaning that if expressions are passed they are both evaluated.
 *
 * See also {@link either}, {@link and}, {@link xor}.
 *
 * @example
 * ```typescript
 * R.or(true, true); //=> true
 * R.or(true, false); //=> true
 * R.or(false, true); //=> true
 * R.or(false, false); //=> false
 * ```
 */
export function or<T, U>(a: T | Falsy, b: U): T | U;
export function or<T>(a: T | Falsy): <U>(b: U) => T | U;

/**
 * Returns the result of applying the `onFailure` function to the value inside a failed `Promise`.
 * This is useful for handling rejected `Promise`s inside function compositions.
 *
 * @example
 * ```typescript
 * const failedFetch = (id: number) => Promise.reject('bad ID');
 * const useDefault = () => ({ firstName: 'Bob', lastName: 'Loblaw' });
 *
 * //recoverFromFailure :: String -> Promise ({ firstName, lastName })
 * const recoverFromFailure = R.pipe(
 *   failedFetch,
 *   R.otherwise(useDefault),
 *   R.andThen(R.pick(['firstName', 'lastName'])),
 * );
 * recoverFromFailure(12345).then(console.log);
 * ```
 */
export function otherwise<A, B>(onError: (error: any) => B | Promise<B>, promise: Promise<A>): Promise<B>;
export function otherwise<A, B>(onError: (error: any) => B | Promise<B>): (promise: Promise<A>) => Promise<B>;

/**
 * Returns the result of "setting" the portion of the given data structure
 * focused by the given lens to the given value.
 *
 * See also {@link view}, {@link set}, {@link lens}, {@link lensIndex}, {@link lensProp}, {@link lensPath}.
 *
 * @example
 * ```typescript
 * const headLens = R.lensIndex<string>(0);
 *
 * R.over(headLens, R.toUpper, ['foo', 'bar', 'baz']); //=> ['FOO', 'bar', 'baz']
 * ```
 */
export function over<S, A>(lens: Lens<S, A>, fn: (a: A) => A, value: S): S;
export function over<S, A>(lens: Lens<S, A>, fn: (a: A) => A): (value: S) => S;
export function over<S, A>(lens: Lens<S, A>): (fn: (a: A) => A, value: S) => S;

/**
 * Takes two arguments, `fst` and `snd`, and returns `[fst, snd]`.
 *
 * See also {@link objOf}, {@link of}.
 *
 * @example
 * ```typescript
 * R.pair('foo', 'bar'); //=> ['foo', 'bar']
 * ```
 */
export function pair<F, S>(fst: F, snd: S): [F, S];
export function pair<F>(fst: F): <S>(snd: S) => [F, S];

/**
 * Takes a function `f` and a list of arguments, and returns a function `g`.
 * When applied, `g` returns the result of applying `f` to the arguments provided initially
 * followed by the arguments provided to `g`.
 *
 * See also {@link partialRight}, {@link curry}.
 *
 * @example
 * ```typescript
 * const multiply2 = (a: number, b: number) => a * b;
 * const double = R.partial(multiply2, [2]);
 * double(3); //=> 6
 *
 * const greet = (salutation: string, title: string, firstName: string, lastName: string) =>
 *   salutation + ', ' + title + ' ' + firstName + ' ' + lastName + '!';
 *
 * const sayHello = R.partial(greet, ['Hello']);
 * const sayHelloToMs = R.partial(sayHello, ['Ms.']);
 * sayHelloToMs('Jane', 'Jones'); //=> 'Hello, Ms. Jane Jones!'
 * ```
 */
export function partial<V0, V1, T>(fn: (x0: V0, x1: V1) => T, args: [V0]): (x1: V1) => T;
export function partial<V0, V1, V2, T>(fn: (x0: V0, x1: V1, x2: V2) => T, args: [V0, V1]): (x2: V2) => T;
export function partial<V0, V1, V2, T>(fn: (x0: V0, x1: V1, x2: V2) => T, args: [V0]): (x1: V1, x2: V2) => T;
export function partial<V0, V1, V2, V3, T>(
    fn: (x0: V0, x1: V1, x2: V2, x3: V3) => T,
    args: [V0, V1, V2],
): (x2: V3) => T;
export function partial<V0, V1, V2, V3, T>(
    fn: (x0: V0, x1: V1, x2: V2, x3: V3) => T,
    args: [V0, V1],
): (x2: V2, x3: V3) => T;
export function partial<V0, V1, V2, V3, T>(
    fn: (x0: V0, x1: V1, x2: V2, x3: V3) => T,
    args: [V0],
): (x1: V1, x2: V2, x3: V3) => T;

export function partial<T>(fn: (...args: any[]) => T, args: unknown[]): (...args: unknown[]) => T;

/**
 * Takes a function `f` and an object, and returns a function `g`.
 * When applied, `g` returns the result of applying `f` to the object
 * provided initially merged deeply (right) with the object provided as an argument to `g`.
 *
 * See also {@link partial}, {@link partialRight}, {@link curry}, {@link mergeDeepRight}.
 *
 * @example
 * ```typescript
 * const multiply2 = ({ a, b }: { a: number, b: number }) => a * b;
 * const double = R.partialObject(multiply2, { a: 2 });
 * double({ b: 2 }); //=> 4
 *
 * type GreetArgs = {
 *     salutation: string;
 *     title: string;
 *     firstName: string;
 *     lastName: string;
 * };
 *
 * const greet = ({ salutation, title, firstName, lastName }: GreetArgs) =>
 *   salutation + ', ' + title + ' ' + firstName + ' ' + lastName + '!';
 *
 * const sayHello = R.partialObject(greet, { salutation: 'Hello' });
 * const sayHelloToMs = R.partialObject(sayHello, { title: 'Ms.' });
 * sayHelloToMs({ firstName: 'Jane', lastName: 'Jones' }); //=> 'Hello, Ms. Jane Jones!'
 * ```
 */
// NOTE: The objects are merged deeply - meaning this should be `DeepOmit` (ideally `& Partial<Omitted>` too)
export function partialObject<T extends P1, P1, R>(fn: (value: T) => R, partial: P1): (value: Omit<T, keyof P1>) => R;
export function partialObject<T, R>(fn: (value: T) => R): <P1>(partial: P1) => (value: Omit<T, keyof P1>) => R;

/**
 * Takes a function `f` and a list of arguments, and returns a function `g`.
 * When applied, `g` returns the result of applying `f` to the arguments
 * provided to `g` followed by the arguments provided initially.
 *
 * See also {@link partial}.
 *
 * @example
 * ```typescript
 * const greet = (salutation: string, title: string, firstName: string, lastName: string) =>
 * salutation + ', ' + title + ' ' + firstName + ' ' + lastName + '!';
 *
 * const greetMsJaneJones = R.partialRight(greet, ['Ms.', 'Jane', 'Jones']);
 *
 * greetMsJaneJones('Hello'); //=> 'Hello, Ms. Jane Jones!'
 * ```
 */
export function partialRight<V0, V1, T>(fn: (x0: V0, x1: V1) => T, args: [V1]): (x1: V0) => T;
export function partialRight<V0, V1, V2, T>(fn: (x0: V0, x1: V1, x2: V2) => T, args: [V1, V2]): (x2: V0) => T;
export function partialRight<V0, V1, V2, T>(fn: (x0: V0, x1: V1, x2: V2) => T, args: [V2]): (x1: V0, x2: V1) => T;
export function partialRight<V0, V1, V2, V3, T>(
    fn: (x0: V0, x1: V1, x2: V2, x3: V3) => T,
    args: [V1, V2, V3],
): (x0: V0) => T;
export function partialRight<V0, V1, V2, V3, T>(
    fn: (x0: V0, x1: V1, x2: V2, x3: V3) => T,
    args: [V2, V3],
): (x0: V0, x1: V1) => T;
export function partialRight<V0, V1, V2, V3, T>(
    fn: (x0: V0, x1: V1, x2: V2, x3: V3) => T,
    args: [V3],
): (x0: V0, x1: V1, x2: V2) => T;

export function partialRight<T>(fn: (...args: any[]) => T, args: unknown[]): (...args: unknown[]) => T;

/**
 * Takes a predicate and a list or other `Filterable` object
 * and returns the elements split into two lists
 * based on whether the element satisfied the predicate.
 * Filterable objects include plain objects
 * and objects with a `filter` method such as `Array`.
 *
 * See also {@link filter}, {@link reject}.
 *
 * @example
 * ```typescript
 * R.partition(R.includes('s'), ['sss', 'ttt', 'foo', 'bars']);
 * // => [ [ 'sss', 'bars' ],  [ 'ttt', 'foo' ] ]
 *
 * R.partition(R.includes('s'), { a: 'sss', b: 'ttt', foo: 'bars' });
 * // => [ { a: 'sss', foo: 'bars' }, { b: 'ttt' }  ]
 * ```
 */
export function partition(fn: (a: string) => boolean, list: readonly string[]): [string[], string[]];
export function partition<T>(fn: (a: T) => boolean, list: readonly T[]): [T[], T[]];
export function partition<T>(fn: (a: T) => boolean): (list: readonly T[]) => [T[], T[]];
export function partition(fn: (a: string) => boolean): (list: readonly string[]) => [string[], string[]];

/**
 * Retrieve the value at a given path.
 *
 * See also {@link prop}, {@link nth}.
 *
 * @example
 * ```typescript
 * R.path(['a', 'b'], {a: {b: 2}});             //=> 2
 * R.path(['a', 'b'], {c: {b: 2}});             //=> undefined
 * R.path(['a', 'b', 0], {a: {b: [1, 2, 3]}});  //=> 1
 * R.path(['a', 'b', -2], {a: {b: [1, 2, 3]}}); //=> 2
 * ```
 */
export function path<S, K0 extends keyof S = keyof S>(path: [K0], obj: S): S[K0];
export function path<S, K0 extends keyof S = keyof S, K1 extends keyof S[K0] = keyof S[K0]>(path: [K0, K1], obj: S): S[K0][K1];
export function path<
    S,
    K0 extends keyof S = keyof S,
    K1 extends keyof S[K0] = keyof S[K0],
    K2 extends keyof S[K0][K1] = keyof S[K0][K1]
>(path: [K0, K1, K2], obj: S): S[K0][K1][K2];
export function path<
    S,
    K0 extends keyof S = keyof S,
    K1 extends keyof S[K0] = keyof S[K0],
    K2 extends keyof S[K0][K1] = keyof S[K0][K1],
    K3 extends keyof S[K0][K1][K2] = keyof S[K0][K1][K2],
>(path: [K0, K1, K2, K3], obj: S): S[K0][K1][K2][K3];
export function path<
    S,
    K0 extends keyof S = keyof S,
    K1 extends keyof S[K0] = keyof S[K0],
    K2 extends keyof S[K0][K1] = keyof S[K0][K1],
    K3 extends keyof S[K0][K1][K2] = keyof S[K0][K1][K2],
    K4 extends keyof S[K0][K1][K2][K3] = keyof S[K0][K1][K2][K3],
>(path: [K0, K1, K2, K3, K4], obj: S): S[K0][K1][K2][K3][K4];
export function path<
    S,
    K0 extends keyof S = keyof S,
    K1 extends keyof S[K0] = keyof S[K0],
    K2 extends keyof S[K0][K1] = keyof S[K0][K1],
    K3 extends keyof S[K0][K1][K2] = keyof S[K0][K1][K2],
    K4 extends keyof S[K0][K1][K2][K3] = keyof S[K0][K1][K2][K3],
    K5 extends keyof S[K0][K1][K2][K3][K4] = keyof S[K0][K1][K2][K3][K4],
>(path: [K0, K1, K2, K3, K4, K5], obj: S): S[K0][K1][K2][K3][K4][K5];
export function path<T>(path: Path, obj: any): T | undefined;
export function path<T>(path: Path): (obj: any) => T | undefined;

/**
 * Determines whether a nested path on an object has a specific value,
 * in {@link equals `R.equals`} terms.
 * Most likely used to filter a list.
 *
 * @example
 * ```typescript
 * const user1 = { address: { zipCode: 90210 } };
 * const user2 = { address: { zipCode: 55555 } };
 * const user3 = { name: 'Bob' };
 * const users = [ user1, user2, user3 ];
 * const isFamous = R.pathEq(['address', 'zipCode'], 90210);
 * R.filter(isFamous, users); //=> [ user1 ]
 * ```
 */
export function pathEq(path: Path, val: any, obj: any): boolean;
export function pathEq(path: Path, val: any): (obj: any) => boolean;
export function pathEq(path: Path): _.F.Curry<(a: any, b: any) => boolean>;

/**
 * If the given, non-null object has a value at the given path,
 * returns the value at that path.
 * Otherwise returns the provided default value.
 *
 * @example
 * ```typescript
 * R.pathOr('N/A', ['a', 'b'], {a: {b: 2}}); //=> 2
 * R.pathOr('N/A', ['a', 'b'], {c: {b: 2}}); //=> "N/A"
 * ```
 */
export function pathOr<T>(defaultValue: T, path: Path, obj: any): T;
export function pathOr<T>(defaultValue: T, path: Path): (obj: any) => T;
export function pathOr<T>(defaultValue: T): _.F.Curry<(a: Path, b: any) => T>;

/**
 * Retrieves the values at given paths of an object.
 *
 * See also {@link path}.
 *
 * @example
 * ```typescript
 * R.paths([['a', 'b'], ['p', 0, 'q']], {a: {b: 2}, p: [{q: 3}]}); //=> [2, 3]
 * R.paths([['a', 'b'], ['p', 'r']], {a: {b: 2}, p: [{q: 3}]}); //=> [2, undefined]
 * ```
 */
export function paths<T>(paths: readonly Path[], obj: any): Array<T | undefined>;
export function paths<T>(paths: readonly Path[]): (obj: any) => Array<T | undefined>;

/**
 * Returns `true` if the specified object property at given path satisfies the given predicate;
 * `false` otherwise.
 *
 * See also {@link propSatisfies}, {@link path}.
 *
 * @example
 * ```typescript
 * R.pathSatisfies((y: number) => y > 0, ['x', 'y'], {x: {y: 2}}); //=> true
 * R.pathSatisfies(R.is(Object), [], {x: {y: 2}}); //=> true
 * ```
 */
export function pathSatisfies<T, U>(pred: (val: T) => boolean, path: Path, obj: U): boolean;
export function pathSatisfies<T, U>(pred: (val: T) => boolean, path: Path): (obj: U) => boolean;
export function pathSatisfies<T, U>(pred: (val: T) => boolean): _.F.Curry<(a: Path, b: U) => boolean>;

/**
 * Returns a partial copy of an object containing only the keys specified.
 * If the key does not exist, the property is ignored.
 *
 * See also {@link omit}, {@link props}.
 *
 * @example
 * ```typescript
 * R.pick(['a', 'd'], {a: 1, b: 2, c: 3, d: 4}); //=> {a: 1, d: 4}
 * R.pick(['a', 'e', 'f'], {a: 1, b: 2, c: 3, d: 4}); //=> {a: 1}
 * ```
 */
export function pick<T extends readonly [any, ...any], K extends string | number | symbol>(
    names: readonly K[],
    array: T,
): {
    [P in K as P extends string | number
        ? _.N.Greater<`${T['length']}`, `${P}`> extends 1
            ? P
            : never
        : never]: P extends keyof T ? T[P] : T[number];
};
export function pick<T, K extends string | number | symbol>(
    names: readonly K[],
    obj: T,
): { [P in keyof T as P extends K ? P : never]: T[P] };
export function pick<K extends string | number | symbol>(
    names: readonly K[],
): <T extends readonly [any, ...any] | object>(
    obj: T,
) => T extends readonly [any, ...any]
    ? {
          [P in K as P extends string | number
              ? _.N.Greater<`${T['length']}`, `${P}`> extends 1
                  ? P
                  : never
              : never]: P extends keyof T ? T[P] : T[number];
      }
    : { [P in keyof T as P extends K ? P : never]: T[P] };

/**
 * Similar to `pick` except that this one includes a `key: undefined` pair for properties that don't exist.
 *
 * @example
 * ```typescript
 * R.pickAll(['a', 'd'], {a: 1, b: 2, c: 3, d: 4}); //=> {a: 1, d: 4}
 * R.pickAll(['a', 'e', 'f'], {a: 1, b: 2, c: 3, d: 4}); //=> {a: 1, e: undefined, f: undefined}
 * ```
 */
export function pickAll<T, K extends keyof T>(names: readonly K[], obj: T): Pick<T, K>;
export function pickAll<T, U>(names: readonly string[], obj: T): U;
export function pickAll(names: readonly string[]): <T, U>(obj: T) => U;

/**
 * Returns a partial copy of an object containing only the keys that satisfy the supplied predicate.
 *
 * @example
 * ```typescript
 * const isUpperCase = <T>(_val: T, key: string) => key.toUpperCase() === key;
 * R.pickBy(isUpperCase, {a: 1, b: 2, A: 3, B: 4}); //=> {A: 3, B: 4}
 * ```
 */
export function pickBy<T, U>(pred: ObjPred<T>, obj: T): U;
export function pickBy<T>(pred: ObjPred<T>): <U, V extends T>(obj: V) => U;

/**
 * Creates a new function that runs each of the functions supplied as parameters in turn,
 * passing the return value of each function invocation to the next function invocation,
 * beginning with whatever arguments were passed to the initial invocation.
 *
 * Performs left-to-right function composition.
 * The first argument may have any arity; the remaining arguments must be unary.
 *
 * In some libraries this function is named `sequence`.
 *
 * @note The result of `pipe` is not automatically curried.
 *
 * See also {@link compose}.
 *
 * @example
 * ```typescript
 * const f = R.pipe(Math.pow, R.negate, R.inc);
 *
 * f(3, 4); // -(3^4) + 1
 * ```
 */
export function pipe<TArgs extends any[], R1, R2, R3, R4, R5, R6, R7, TResult>(
    ...funcs: [
        f1: (...args: TArgs) => R1,
        f2: (a: R1) => R2,
        f3: (a: R2) => R3,
        f4: (a: R3) => R4,
        f5: (a: R4) => R5,
        f6: (a: R5) => R6,
        f7: (a: R6) => R7,
        ...func: Array<(a: any) => any>,
        fnLast: (a: any) => TResult,
    ]
): (...args: TArgs) => TResult; // fallback overload if number of piped functions greater than 7
export function pipe<TArgs extends any[], R1, R2, R3, R4, R5, R6, R7>(
    f1: (...args: TArgs) => R1,
    f2: (a: R1) => R2,
    f3: (a: R2) => R3,
    f4: (a: R3) => R4,
    f5: (a: R4) => R5,
    f6: (a: R5) => R6,
    f7: (a: R6) => R7,
): (...args: TArgs) => R7;
export function pipe<TArgs extends any[], R1, R2, R3, R4, R5, R6>(
    f1: (...args: TArgs) => R1,
    f2: (a: R1) => R2,
    f3: (a: R2) => R3,
    f4: (a: R3) => R4,
    f5: (a: R4) => R5,
    f6: (a: R5) => R6,
): (...args: TArgs) => R6;
export function pipe<TArgs extends any[], R1, R2, R3, R4, R5>(
    f1: (...args: TArgs) => R1,
    f2: (a: R1) => R2,
    f3: (a: R2) => R3,
    f4: (a: R3) => R4,
    f5: (a: R4) => R5,
): (...args: TArgs) => R5;
export function pipe<TArgs extends any[], R1, R2, R3, R4>(
    f1: (...args: TArgs) => R1,
    f2: (a: R1) => R2,
    f3: (a: R2) => R3,
    f4: (a: R3) => R4,
): (...args: TArgs) => R4;
export function pipe<TArgs extends any[], R1, R2, R3>(
    f1: (...args: TArgs) => R1,
    f2: (a: R1) => R2,
    f3: (a: R2) => R3,
): (...args: TArgs) => R3;
export function pipe<TArgs extends any[], R1, R2>(
    f1: (...args: TArgs) => R1,
    f2: (a: R1) => R2,
): (...args: TArgs) => R2;
export function pipe<TArgs extends any[], R1>(f1: (...args: TArgs) => R1): (...args: TArgs) => R1;

/**
 * Performs left-to-right function composition using transforming function.
 * The first function may have any arity; the remaining functions must be unary.
 *
 * @note The result of `pipeWith` is not automatically curried. Transforming function is not used on the first argument.
 *
 * See also {@link composeWith}, {@link pipe}.
 *
 * @example
 * ```typescript
 * const pipeWhileNotNil = R.pipeWith((f, res) => R.isNil(res) ? res : f(res));
 * const f = pipeWhileNotNil([Math.pow, R.negate, R.inc])
 *
 * f(3, 4); // -(3^4) + 1
 * ```
 */
export function pipeWith<TArgs extends any[], TResult>(
    transformer: (fn: AnyFunction, intermediateResult: any) => any,
    fns: AtLeastOneFunctionsFlow<TArgs, TResult>,
): (...args: TArgs) => TResult;
export function pipeWith(
    transformer: (fn: AnyFunction, intermediateResult: any) => any,
): <TArgs extends any[], TResult>(fns: AtLeastOneFunctionsFlow<TArgs, TResult>) => (...args: TArgs) => TResult;

/**
 * Returns a new list by plucking the same named property off all objects in the list supplied.
 *
 * `pluck` will work on any functor in addition to arrays, as it is equivalent to `R.map(R.prop(k), f)`.
 *
 * See also {@link project}, {@link prop}, {@link props}.
 *
 * @example
 * ```typescript
 * var getAges = R.pluck('age');
 * const people = [{name: 'fred', age: 29}, {name: 'wilma', age: 27}]
 * getAges(people); //=> [29, 27]
 *
 * R.pluck(0, [[1, 2], [3, 4]]);               //=> [1, 3]
 * R.pluck('val', {a: {val: 3}, b: {val: 5}}); //=> {a: 3, b: 5}
 * ```
 */
export function pluck<K extends keyof T, T>(p: K, list: readonly T[]): Array<T[K]>;
export function pluck<T>(p: number, list: ReadonlyArray<{ [k: number]: T }>): T[];
export function pluck<P extends string>(p: P): <T>(list: ReadonlyArray<Record<P, T>>) => T[];
export function pluck(p: number): <T>(list: ReadonlyArray<{ [k: number]: T }>) => T[];

/**
 * Returns a new list with the given element at the front,
 * followed by the contents of the list.
 *
 * See also {@link append}.
 *
 * @example
 * ```typescript
 * R.prepend('fee', ['fi', 'fo', 'fum']); //=> ['fee', 'fi', 'fo', 'fum']
 * ```
 */
export function prepend<T>(el: T, list: readonly T[]): T[];
export function prepend<T>(el: T): (list: readonly T[]) => T[];

/**
 * Multiplies together all the elements of a list.
 *
 * See also {@link reduce}.
 *
 * @example
 * ```typescript
 * R.product([2,4,6,8,100,1]); //=> 38400
 * ```
 */
export function product(list: readonly number[]): number;

/**
 * Reasonable analog to SQL `select` statement.
 *
 * See also {@link pluck}, {@link props}, {@link prop}.
 *
 * @example
 * ```typescript
 * const abby = {name: 'Abby', age: 7, hair: 'blond', grade: 2};
 * const fred = {name: 'Fred', age: 12, hair: 'brown', grade: 7};
 * const kids = [abby, fred];
 * R.project(['name', 'grade'], kids); //=> [{name: 'Abby', grade: 2}, {name: 'Fred', grade: 7}]
 * ```
 */
export function project<T, U>(props: readonly string[], objs: readonly T[]): U[];
export function project<T, U>(props: readonly string[]): (objs: readonly T[]) => U[];

/**
 * Takes two functions as pre- and post- processors respectively for a third function,
 * i.e. `promap(f, g, h)(x) === g(h(f(x)))`.
 * Dispatches to the `promap` method of the third argument, if present,
 * according to the FantasyLand Profunctor spec.
 * Acts as a transducer if a transformer is given in profunctor position.
 *
 * See also {@link transduce}.
 *
 * @example
 * ```typescript
 * const decodeChar = R.promap((s: string) => s.charCodeAt(0), String.fromCharCode, R.add(-8))
 * const decodeString = R.promap(R.split(''), R.join(''), R.map(decodeChar))
 * decodeString("ziuli") //=> "ramda"
 * ```
 */
export function promap<A, B, C, D>(pre: (value: A) => B, post: (value: C) => D, fn: (value: B) => C): (value: A) => D;
export function promap<A, B, C, D>(
    pre: (value: A) => B,
    post: (value: C) => D,
): (fn: (value: B) => C) => (value: A) => D;
export function promap<A, B>(
    pre: (value: A) => B,
): <C, D>(post: (value: C) => D, fn: (value: B) => C) => (value: A) => D;

/**
 * Returns a function that when supplied an object
 * returns the indicated property of that object, if it exists.
 *
 * See also {@link propOr}, {@link path}, {@link props}, {@link pluck}, {@link project}, {@link nth}.
 *
 * @example
 * ```typescript
 * R.prop('x', {x: 100}); //=> 100
 * R.prop(0, [100]); //=> 100
 * R.compose(R.inc, R.prop<number>('x'))({ x: 3 }) //=> 4
 * ```
 */
export function prop<_, T>(__: Placeholder, value: T): {
    <P extends keyof Exclude<T, undefined>>(p: P): Prop<T, P>;
    <P extends keyof never>(p: P): Prop<T, P>;
};
export function prop<V>(__: Placeholder, value: unknown): (p: keyof never) => V;
export function prop<_, P extends keyof never, T>(p: P, value: T): Prop<T, P>;
export function prop<V>(p: keyof never, value: unknown): V;
export function prop<_, P extends keyof never>(p: P): <T>(value: T) => Prop<T, P>;
export function prop<V>(p: keyof never): (value: unknown) => V;

// NOTE: `hair` property was added to `alois` to make example work.
// A union of two types is a valid usecase but doesn't work with current types
/**
 * Returns `true` if the specified object property is equal,
 * in `R.equals` terms, to the given value; `false` otherwise.
 * You can test multiple properties with `R.whereEq`.
 *
 * See also {@link whereEq}, {@link propSatisfies}, {@link equals}.
 *
 * @example
 * ```typescript
 * const abby = {name: 'Abby', age: 7, hair: 'blond'};
 * const fred = {name: 'Fred', age: 12, hair: 'brown'};
 * const rusty = {name: 'Rusty', age: 10, hair: 'brown'};
 * const alois = {name: 'Alois', age: 15, hair: 'brown', disposition: 'surly'};
 * const kids = [abby, fred, rusty, alois];
 * const hasBrownHair = R.propEq('hair', 'brown');
 * R.filter(hasBrownHair, kids); //=> [fred, rusty]
 * ```
 */
export function propEq<K extends string | number>(name: K, val: any, obj: Record<K, any>): boolean;
export function propEq<K extends string | number>(name: K, val: any): (obj: Record<K, any>) => boolean;
export function propEq<K extends string | number>(
    name: K,
): {
    (val: any, obj: Record<K, any>): boolean;
    (val: any): (obj: Record<K, any>) => boolean;
};

/**
 * Returns `true` if the specified object property is of the given type; `false` otherwise.
 *
 * See also {@link is}, {@link propSatisfies}.
 *
 * @example
 * ```typescript
 * R.propIs(Number, 'x', {x: 1, y: 2});  //=> true
 * R.propIs(Number, 'x', {x: 'foo'});    //=> false
 * R.propIs(Number, 'x', {});            //=> false
 * ```
 */
export function propIs<C extends AnyFunction, K extends PropertyKey>(
    type: C,
    name: K,
    obj: any,
): obj is Record<K, ReturnType<C>>;
export function propIs<C extends AnyConstructor, K extends PropertyKey>(
    type: C,
    name: K,
    obj: any,
): obj is Record<K, InstanceType<C>>;
export function propIs<C extends AnyFunction, K extends PropertyKey>(
    type: C,
    name: K,
): (obj: any) => obj is Record<K, ReturnType<C>>;
export function propIs<C extends AnyConstructor, K extends PropertyKey>(
    type: C,
    name: K,
): (obj: any) => obj is Record<K, InstanceType<C>>;
export function propIs<C extends AnyFunction>(
    type: C,
): {
    <K extends keyof any>(name: K, obj: any): obj is Record<K, ReturnType<C>>;
    <K extends keyof any>(name: K): (obj: any) => obj is Record<K, ReturnType<C>>;
};
export function propIs<C extends AnyConstructor>(
    type: C,
): {
    <K extends keyof any>(name: K, obj: any): obj is Record<K, InstanceType<C>>;
    <K extends keyof any>(name: K): (obj: any) => obj is Record<K, InstanceType<C>>;
};

/**
 * Return the specified property of the given non-null object
 * if the property is present and its value is not `null`, `undefined` or `NaN`.
 *
 * Otherwise the first argument is returned.
 *
 * See also {@link prop}.
 *
 * @example
 * ```typescript
 * const alice = {
 *   name: 'ALICE',
 *   age: 101
 * };
 * const favorite = R.prop('favoriteLibrary');
 * const favoriteWithDefault = R.propOr('Ramda', 'favoriteLibrary');
 *
 * favorite(alice as any);     //=> undefined
 * favoriteWithDefault(alice); //=> 'Ramda'
 * ```
 */
export function propOr<T, U>(val: T, __: Placeholder, obj: U): <V>(p: string) => V;
export function propOr<U>(__: Placeholder, p: string, obj: U): <T, V>(val: T) => V;
export function propOr<T, U, V>(val: T, p: string, obj: U): V;
export function propOr<T>(val: T, p: string): <U, V>(obj: U) => V;
export function propOr<T>(val: T): <U, V>(p: string, obj: U) => V;

/**
 * Acts as multiple `prop`: array of keys in, array of values out. Preserves order.
 *
 * See also {@link prop}, {@link pluck}, {@link project}.
 *
 * @example
 * ```typescript
 * R.props(['x', 'y'], {x: 1, y: 2}); //=> [1, 2]
 * R.props(['c', 'a', 'b'], {b: 2, a: 1, c: 3}); //=> [3, 1, 2]
 *
 * const fullName = R.compose(R.join(' '), R.props(['first', 'last']));
 * const tony = {last: 'Bullet-Tooth', age: 33, first: 'Tony'};
 * fullName(tony); //=> 'Tony Bullet-Tooth'
 * ```
 */
export function props<P extends string, T>(ps: readonly P[], obj: Record<P, T>): T[];
export function props<P extends string>(ps: readonly P[]): <T>(obj: Record<P, T>) => T[];
export function props<P extends string, T>(ps: readonly P[]): (obj: Record<P, T>) => T[];

/**
 * Returns `true` if the specified object property satisfies the given predicate; `false` otherwise.
 * You can test multiple properties with `R.where`.
 *
 * See also {@link where}, {@link propEq}, {@link propIs}.
 *
 * @example
 * ```typescript
 * const val = {x: 1, y: 2};
 * R.propSatisfies(x => x > 0, 'x', val); //=> true
 * ```
 */
export function propSatisfies<P, K extends keyof any>(
    pred: (val: any) => val is P,
    name: K,
    obj: any,
): obj is Record<K, P>;
export function propSatisfies<P, K extends keyof any>(
    pred: (val: any) => val is P,
    name: K,
): (obj: any) => obj is Record<K, P>;
export function propSatisfies<P>(pred: (val: any) => val is P): {
    <K extends keyof any>(name: K, obj: any): obj is Record<K, P>;
    <K extends keyof any>(name: K): (obj: any) => obj is Record<K, P>;
};
export function propSatisfies(pred: (val: any) => boolean, name: keyof any, obj: any): boolean;
export function propSatisfies(pred: (val: any) => boolean, name: keyof any): (obj: any) => boolean;
export function propSatisfies(pred: (val: any) => boolean): _.F.Curry<(a: keyof any, b: any) => boolean>;

/**
 * Returns a list of numbers from `from` (inclusive) to `to` (exclusive).
 * In mathematical terms, `range(a, b)` is equivalent to the half-open interval `[a, b)`.
 *
 * @example
 * ```typescript
 * R.range(1, 5);    //=> [1, 2, 3, 4]
 * R.range(50, 53);  //=> [50, 51, 52]
 * ```
 */
export function range(from: number, to: number): number[];
export function range(from: number): (to: number) => number[];

/**
 * Returns a single item by iterating through the list,
 * successively calling the iterator function and passing it an accumulator value and the current value from the array,
 * and then passing the result to the next call.
 *
 * The iterator function receives two values: `(acc, value)`. It may use `R.reduced` to shortcut the iteration.
 *
 * @note `R.reduce` does not skip deleted or unassigned indices (sparse arrays), unlike the native `Array.prototype.reduce` method.
 *
 * Dispatches to the `reduce` method of the third argument, if present.
 * When doing so, it is up to the user to handle the `R.reduced` shortcutting,
 * as this is not implemented by `reduce`.
 *
 * See also {@link reduced}, {@link addIndex}, {@link reduceRight}.
 *
 * @example
 * ```typescript
 * R.reduce(R.subtract, 0, [1, 2, 3, 4]) //=> ((((0 - 1) - 2) - 3) - 4) = -10
 * //          -               -10
 * //         / \              / \
 * //        -   4           -6   4
 * //       / \              / \
 * //      -   3   ==>     -3   3
 * //     / \              / \
 * //    -   2           -1   2
 * //   / \              / \
 * //  0   1            0   1
 * ```
 */
export function reduce<T, TResult>(
    fn: (acc: TResult, elem: T) => TResult | Reduced<TResult>,
    acc: TResult,
    list: readonly T[],
): TResult;
export function reduce<T, TResult>(
    fn: (acc: TResult, elem: T) => TResult | Reduced<TResult>,
): (acc: TResult, list: readonly T[]) => TResult;
export function reduce<T, TResult>(
    fn: (acc: TResult, elem: T) => TResult | Reduced<TResult>,
    acc: TResult,
): (list: readonly T[]) => TResult;

/**
 * Groups the elements of the list
 * according to the result of calling the string-returning function `keyFn` on each element
 * and reduces the elements of each group to a single value via the reducer function `valueFn`.
 *
 * The value function receives two values: `(acc, value)`.
 * It may use `R.reduced` to short circuit the iteration.
 *
 * This function is basically a more general `R.groupBy` function.
 *
 * Acts as a transducer if a transformer is given in list position.
 *
 * See also {@link groupBy}, {@link reduce}, {@link reduced}, {@link transduce}.
 *
 * @example
 * ```typescript
 * const groupNames = (acc: string[], { name }: { name: string; }) => acc.concat(name)
 * const toGrade = ({ score }: { score: number; }) =>
 *   score < 65 ? 'F' :
 *   score < 70 ? 'D' :
 *   score < 80 ? 'C' :
 *   score < 90 ? 'B' : 'A'
 *
 * var students = [
 *   {name: 'Abby', score: 83},
 *   {name: 'Bart', score: 62},
 *   {name: 'Curt', score: 88},
 *   {name: 'Dora', score: 92},
 * ]
 *
 * R.reduceBy(groupNames, [], toGrade, students)
 * //=> {"A": ["Dora"], "B": ["Abby", "Curt"], "F": ["Bart"]}
 * ```
 */
export function reduceBy<T, TResult>(
    valueFn: (acc: TResult, elem: T) => TResult,
    acc: TResult,
    keyFn: (elem: T) => string,
    list: readonly T[],
): { [index: string]: TResult };
export function reduceBy<T, TResult>(
    valueFn: (acc: TResult, elem: T) => TResult,
    acc: TResult,
    keyFn: (elem: T) => string,
): (list: readonly T[]) => { [index: string]: TResult };
export function reduceBy<T, TResult>(
    valueFn: (acc: TResult, elem: T) => TResult,
    acc: TResult,
): _.F.Curry<(a: (elem: T) => string, b: readonly T[]) => { [index: string]: TResult }>;
export function reduceBy<T, TResult>(
    valueFn: (acc: TResult, elem: T) => TResult,
): _.F.Curry<(a: TResult, b: (elem: T) => string, c: readonly T[]) => { [index: string]: TResult }>;

/**
 * Returns a value wrapped to indicate that it is the final value of the `R.reduce` and `R.transduce` functions.
 * The returned value should be considered a black box:
 * the internal structure is not guaranteed to be stable.
 *
 * This optimization is available to the below functions:
 *  - `R.reduce`
 *  - `R.reduceWhile`
 *  - `R.reduceBy`
 *  - `R.reduceRight`
 *  - `R.transduce`
 *
 * See also {@link reduce}, {@link reduceWhile}, {@link reduceBy}, {@link reduceRight}, {@link transduce}.
 *
 * @example
 * ```typescript
 * R.reduce(
 *  (acc, item) => item > 3 ? R.reduced(acc) : acc.concat(item),
 *  [] as number[],
 *  [1, 2, 3, 4, 5]) // [1, 2, 3]
 * ```
 */
export function reduced<T>(elem: T): Reduced<T>;

// NOTE: the example currently does not work, even if `R.__` overloads are removed
/**
 * Returns a single item by iterating through the list,
 * successively calling the iterator function
 * and passing it an accumulator value and the current value from the array,
 * and then passing the result to the next call.
 *
 * Similar to `R.reduce`, except moves through the input list from the right to the left.
 *
 * The iterator function receives two values: `(value, acc)`,
 * reversed compared to that of `R.reduce`'s iterator function.
 * `reduceRight` may use `R.reduced` to short circuit the iteration.
 *
 * @note `R.reduceRight` does not skip deleted or unassigned indices (sparse arrays),
 * unlike the native `Array.prototype.reduceRight` method.
 *
 * See also {@link reduce}, {@link addIndex}, {@link reduced}.
 *
 * @example
 * ```typescript
 * R.reduceRight(R.subtract, 0, [1, 2, 3, 4]) // => (1 - (2 - (3 - (4 - 0)))) = -2
 * //    -               -2
 * //   / \              / \
 * //  1   -            1   3
 * //     / \              / \
 * //    2   -     ==>    2  -1
 * //       / \              / \
 * //      3   -            3   4
 * //         / \              / \
 * //        4   0            4   0
 * ```
 */
export function reduceRight<T, TResult>(
    fn: (elem: T, acc: TResult) => TResult,
    acc: TResult,
    list: readonly T[],
): TResult;
export function reduceRight<T, TResult>(
    fn: (elem: T, acc: TResult) => TResult,
): (acc: TResult, list: readonly T[]) => TResult;
export function reduceRight<T, TResult>(
    fn: (elem: T, acc: TResult) => TResult,
    acc: TResult,
): (list: readonly T[]) => TResult;

/**
 * Like `R.reduce`, `R.reduceWhile` returns a single item by iterating through the list,
 * successively calling the iterator function.
 * `R.reduceWhile` also takes a predicate that is evaluated before each step.
 * If the predicate returns a falsy value,
 * it "short-circuits" the iteration and returns the current value of the accumulator.
 *
 * See also {@link reduce}, {@link reduced}.
 *
 * @example
 * ```typescript
 * const isOdd = (acc: number, x: number) => x % 2 !== 0;
 * const xs = [1, 3, 5, 60, 777, 800];
 * R.reduceWhile(isOdd, R.add, 0, xs); //=> 9
 *
 * const ys = [2, 4, 6]
 * R.reduceWhile(isOdd, R.add, 111, ys); //=> 111
 * ```
 */
export function reduceWhile<T, TResult>(
    predicate: (acc: TResult, elem: T) => boolean,
    fn: (acc: TResult, elem: T) => TResult,
    acc: TResult,
    list: readonly T[],
): TResult;
export function reduceWhile<T, TResult>(
    predicate: (acc: TResult, elem: T) => boolean,
    fn: (acc: TResult, elem: T) => TResult,
    acc: TResult,
): (list: readonly T[]) => TResult;
export function reduceWhile<T, TResult>(
    predicate: (acc: TResult, elem: T) => boolean,
    fn: (acc: TResult, elem: T) => TResult,
): _.F.Curry<(a: TResult, b: readonly T[]) => TResult>;
export function reduceWhile<T, TResult>(
    predicate: (acc: TResult, elem: T) => boolean,
): _.F.Curry<(a: (acc: TResult, elem: T) => TResult, b: TResult, c: readonly T[]) => TResult>;

/**
 * The complement of `R.filter`.
 *
 * Acts as a transducer if a transformer is given in list position.
 * `Filterable` objects include plain objects or any object that has a `filter` method such as `Array`.
 *
 * See also {@link filter}, {@link transduce}, {@link addIndex}.
 *
 * @example
 * ```typescript
 * const isOdd = (n: number) => n % 2 !== 0;
 *
 * R.reject(isOdd, [1, 2, 3, 4]); //=> [2, 4]
 *
 * R.reject(isOdd, {a: 1, b: 2, c: 3, d: 4}); //=> {b: 2, d: 4}
 * ```
 */
export function reject<A, P extends A>(
    pred: (val: A) => val is P,
): {
    <B extends A>(list: readonly B[]): Array<Exclude<B, P>>;
    <B extends A>(dict: Dictionary<B>): Dictionary<Exclude<B, P>>;
};
export function reject<T>(
    pred: (value: T) => boolean,
): <P extends T, C extends readonly P[] | Dictionary<P>>(collection: C) => C;
export function reject<A, B extends A, P extends A>(
    pred: (val: A) => val is P,
    list: readonly B[],
): Array<Exclude<B, P>>;
export function reject<A, B extends A, P extends A>(
    pred: (val: A) => val is P,
    dict: Dictionary<B>,
): Dictionary<Exclude<B, P>>;
export function reject<T, C extends readonly T[] | Dictionary<T>>(pred: (value: T) => boolean, collection: C): C;

/**
 * Returns a copy of the given list
 * with the given number of elements removed,
 * starting at the given start index.
 *
 * See also {@link without}.
 *
 * @example
 * ```typescript
 * R.remove(2, 3, [1,2,3,4,5,6,7,8]); //=> [1,2,6,7,8]
 * ```
 */
export function remove<T>(start: number, count: number, list: readonly T[]): T[];
export function remove<T>(start: number): {
    (count: number, list: readonly T[]): T[];
    (count: number): (list: readonly T[]) => T[];
};
export function remove<T>(start: number, count: number): (list: readonly T[]) => T[];

/**
 * Returns a fixed list of size `n`, containing a specified identical value.
 *
 * See also {@link times}.
 *
 * @example
 * ```typescript
 * R.repeat('hi', 5); //=> ['hi', 'hi', 'hi', 'hi', 'hi']
 *
 * const obj = {};
 * const repeatedObjs = R.repeat(obj, 5); //=> [{}, {}, {}, {}, {}]
 * repeatedObjs[0] === repeatedObjs[1]; //=> true
 * ```
 */
export function repeat<T>(a: T, n: number): T[];
export function repeat<T>(a: T): (n: number) => T[];

/**
 * Replace a substring or regex match in a string with a replacement.
 *
 * The first two parameters correspond to the parameters of `String.prototype.replace`,
 * so the second parameter can also be a function.
 *
 * @example
 * ```typescript
 * R.replace('foo', 'bar', 'foo foo foo'); //=> 'bar foo foo'
 * R.replace(/foo/, 'bar', 'foo foo foo'); //=> 'bar foo foo'
 *
 * // Use the "g" (global) flag to replace all occurrences:
 * R.replace(/foo/g, 'bar', 'foo foo foo'); //=> 'bar bar bar'
 * ```
 */
export function replace(
    pattern: RegExp | string,
    replacement: string | ((match: string, ...args: readonly any[]) => string),
    str: string,
): string;
export function replace(
    pattern: RegExp | string,
    replacement: string | ((match: string, ...args: readonly any[]) => string),
): (str: string) => string;
export function replace(
    pattern: RegExp | string,
): (replacement: string | ((match: string, ...args: readonly any[]) => string)) => (str: string) => string;

/**
 * Returns a new list or string with the elements in reverse order.
 *
 * @example
 * ```typescript
 * R.reverse([1, 2, 3]);  //=> [3, 2, 1]
 * R.reverse([1, 2]);     //=> [2, 1]
 * R.reverse([1]);        //=> [1]
 * R.reverse([]);         //=> []
 *
 * R.reverse('abc');      //=> 'cba'
 * R.reverse('ab');       //=> 'ba'
 * R.reverse('a');        //=> 'a'
 * R.reverse('');         //=> ''
 * ```
 */
export function reverse<T>(list: readonly T[]): T[];
export function reverse(str: string): string;

/**
 * Similar to `R.reduce`, but returns a list of successively reduced values from the left.
 *
 * See also {@link reduce}, {@link mapAccum}.
 *
 * @example
 * ```typescript
 * const numbers = [1, 2, 3, 4];
 * const factorials = R.scan(R.multiply, 1 as number, numbers); //=> [1, 1, 2, 6, 24]
 * ```
 */
export function scan<T, TResult>(fn: (acc: TResult, elem: T) => any, acc: TResult, list: readonly T[]): TResult[];
export function scan<T, TResult>(fn: (acc: TResult, elem: T) => any, acc: TResult): (list: readonly T[]) => TResult[];
export function scan<T, TResult>(fn: (acc: TResult, elem: T) => any): (acc: TResult, list: readonly T[]) => TResult[];

/**
 * Returns the result of "setting" the portion of the given data structure focused by the given lens
 * to the given value.
 *
 * See also {@link view}, {@link over}, {@link lens}, {@link lensIndex}, {@link lensProp}, {@link lensPath}.
 *
 * @example
 * ```typescript
 * const xLens = R.lensProp<'x', number>('x');
 *
 * const point = {x: 1, y: 2};
 * R.set(xLens, 4, point); //=> {x: 4, y: 2}
 * R.set(xLens, 8, point); //=> {x: 8, y: 2}
 * ```
 */
export function set<S, A>(lens: Lens<S, A>, a: A, obj: S): S;
export function set<S, A>(lens: Lens<S, A>, a: A): (obj: S) => S;
export function set<S, A>(lens: Lens<S, A>): (a: A, obj: S) => S;

/**
 * Returns the elements of the given list or string
 * from `fromIndex` (inclusive) to `toIndex` (exclusive).
 *
 * Dispatches to the `slice` method of the third argument, if present.
 *
 * @example
 * ```typescript
 * R.slice(1, 3, ['a', 'b', 'c', 'd']);        //=> ['b', 'c']
 * R.slice(1, Infinity, ['a', 'b', 'c', 'd']); //=> ['b', 'c', 'd']
 * R.slice(0, -1, ['a', 'b', 'c', 'd']);       //=> ['a', 'b', 'c']
 * R.slice(-3, -1, ['a', 'b', 'c', 'd']);      //=> ['b', 'c']
 * R.slice(0, 3, 'ramda');                     //=> 'ram'
 * ```
 */
export function slice(a: number, b: number, list: string): string;
export function slice<T>(a: number, b: number, list: readonly T[]): T[];
export function slice(
    a: number,
    b: number,
): {
    <T>(list: readonly T[]): T[];
    (list: string): string;
};
export function slice(a: number): {
    <T>(b: number, list: readonly T[]): T[];
    (b: number, list: string): string;
};

/**
 * Returns a copy of the list, sorted according to the comparator function,
 * which should accept two values at a time and return:
 *  - a negative number if the first value is smaller,
 *  - a positive number if it's larger, and
 *  - zero if they are equal.
 *
 * See also {@link sortBy}, {@link sortWith}, {@link ascend}, {@link descend}.
 *
 * @example
 * ```typescript
 * R.sort(R.subtract, [4,2,7,5]); //=> [2, 4, 5, 7]
 * ```
 */
export function sort<T>(fn: (a: T, b: T) => number, list: readonly T[]): T[];
export function sort<T>(fn: (a: T, b: T) => number): (list: readonly T[]) => T[];

/**
 * Sorts the list according to a key generated by the supplied function.
 *
 * See also {@link sort}, {@link sortWith}, {@link ascend}, {@link descend}.
 *
 * @example
 * ```typescript
 * type Person = { name: string; age: number; };
 *
 * const sortByFirstItem = R.sortBy(R.prop(0));
 * const pairs = [[-1, 1], [-2, 2], [-3, 3]];
 * sortByFirstItem(pairs); //=> [[-3, 3], [-2, 2], [-1, 1]]
 * const sortByNameCaseInsensitive = R.sortBy<Person>(R.compose(R.toLower, R.prop('name')));
 * const alice = {
 *   name: 'ALICE',
 *   age: 101
 * };
 * const bob = {
 *   name: 'Bob',
 *   age: -10
 * };
 * const clara = {
 *   name: 'clara',
 *   age: 314.159
 * };
 * const people = [clara, bob, alice];
 * sortByNameCaseInsensitive(people); //=> [alice, bob, clara]
 * ```
 */
export function sortBy<T>(fn: (a: T) => Ord, list: readonly T[]): T[];
export function sortBy<T>(fn: (a: T) => Ord): (list: readonly T[]) => T[];
export function sortBy(fn: (a: any) => Ord): <T>(list: readonly T[]) => T[];

/**
 * Sorts a list according to a list of comparators.
 *
 * See also {@link sort}, {@link sortBy}, {@link ascend}, {@link descend}.
 *
 * @example
 * ```typescript
 * type Person = { age: number; name: string; };
 *
 * const alice = {
 *   name: 'alice',
 *   age: 40
 * };
 * const bob = {
 *   name: 'bob',
 *   age: 30
 * };
 * const clara = {
 *   name: 'clara',
 *   age: 40
 * };
 * const people = [clara, bob, alice];
 * const ageNameSort = R.sortWith<Person>([
 *   R.descend(R.prop('age')),
 *   R.ascend(R.prop('name'))
 * ]);
 * ageNameSort(people); //=> [alice, clara, bob]
 * ```
 */
export function sortWith<T>(fns: ReadonlyArray<(a: T, b: T) => number>, list: readonly T[]): T[];
export function sortWith<T>(fns: ReadonlyArray<(a: T, b: T) => number>): (list: readonly T[]) => T[];

/**
 * Splits a string into an array of strings based on the given separator.
 *
 * See also {@link join}.
 *
 * @example
 * ```typescript
 * const pathComponents = R.split('/');
 * R.tail(pathComponents('/usr/local/bin/node')); //=> ['usr', 'local', 'bin', 'node']
 *
 * R.split('.', 'a.b.c.xyz.d'); //=> ['a', 'b', 'c', 'xyz', 'd']
 * ```
 */
export function split(sep: string | RegExp): (str: string) => string[];
export function split(sep: string | RegExp, str: string): string[];

/**
 * Splits a given list or string at a given index.
 *
 * @example
 * ```typescript
 * R.splitAt(1, [1, 2, 3]);          //=> [[1], [2, 3]]
 * R.splitAt(5, 'hello world');      //=> ['hello', ' world']
 * R.splitAt(-1, 'foobar');          //=> ['fooba', 'r']
 * ```
 */
export function splitAt<T>(index: number, list: readonly T[]): [T[], T[]];
export function splitAt(index: number, list: string): [string, string];
export function splitAt(index: number): {
    <T>(list: readonly T[]): [T[], T[]];
    (list: string): [string, string];
};

/**
 * Splits a collection into slices of the specified length.
 *
 * @example
 * ```typescript
 * R.splitEvery(3, [1, 2, 3, 4, 5, 6, 7]); //=> [[1, 2, 3], [4, 5, 6], [7]]
 * R.splitEvery(3, 'foobarbaz'); //=> ['foo', 'bar', 'baz']
 * ```
 */
export function splitEvery<T>(a: number, list: readonly T[]): T[][];
export function splitEvery(a: number, list: string): string[];
export function splitEvery(a: number): {
    (list: string): string[];
    <T>(list: readonly T[]): T[][];
};

/**
 * Takes a list and a predicate and returns a pair of lists.
 * The first list contains all elements
 * before (but not including) the first element for which the predicate returns a truthy value.
 * The second list contains the rest of the elements.
 * It will be empty if no elements satisfy the predicate.
 *
 * @example
 * ```typescript
 * R.splitWhen(R.equals(2), [1, 2, 3, 1, 2, 3]);   //=> [[1], [2, 3, 1, 2, 3]]
 * ```
 */
export function splitWhen<T>(pred: (val: T) => boolean, list: readonly T[]): [T[], T[]];
export function splitWhen<T>(pred: (val: T) => boolean): <U extends T>(list: readonly U[]) => [U[], U[]];

/**
 * Splits an array into slices on every occurrence of a value.
 *
 * @example
 * ```typescript
 * R.splitWhenever(R.equals(2), [1, 2, 3, 2, 4, 5, 2, 6, 7]); //=> [[1], [3], [4, 5], [6, 7]]
 * ```
 */
export function splitWhenever<T>(pred: (a: T) => boolean, list: T[]): T[][];
export function splitWhenever<T>(pred: (a: T) => boolean): <U extends T>(list: U[]) => U[][];

/**
 * Checks if a list starts with the provided sublist.
 *
 * Similarly, checks if a string starts with the provided substring.
 *
 * See also {@link endsWith}.
 *
 * @example
 * ```typescript
 * R.startsWith('a', 'abc')                //=> true
 * R.startsWith('b', 'abc')                //=> false
 * R.startsWith(['a'], ['a', 'b', 'c'])    //=> true
 * R.startsWith(['b'], ['a', 'b', 'c'])    //=> false
 * ```
 */
export function startsWith(substr: string, str: string): boolean;
export function startsWith(substr: string): (str: string) => boolean;
export function startsWith<T>(subList: readonly T[], list: readonly T[]): boolean;
export function startsWith<T>(subList: readonly T[]): (list: readonly T[]) => boolean;

/**
 * Subtracts two numbers. Equivalent to `a - b` but curried.
 *
 * @example
 * ```typescript
 * R.subtract(10, 8); //=> 2
 *
 * const minus5 = R.subtract(R.__, 5);
 * minus5(17); //=> 12
 *
 * const complementaryAngle = R.subtract(90);
 * complementaryAngle(30); //=> 60
 * complementaryAngle(72); //=> 18
 * ```
 */
export function subtract(__: Placeholder, b: number): (a: number) => number;
export function subtract(__: Placeholder): (b: number, a: number) => number;
export function subtract(a: number, b: number): number;
export function subtract(a: number): (b: number) => number;

/**
 * Adds together all the elements of a list.
 *
 * See also {@link reduce}.
 *
 * @example
 * ```typescript
 * R.sum([2,4,6,8,100,1]); //=> 121
 * ```
 */
export function sum(list: readonly number[]): number;

/**
 * Finds the set (i.e. no duplicates) of all elements
 * contained in the first or second list, but not both.
 *
 * See also {@link symmetricDifferenceWith}, {@link difference}, {@link differenceWith}.
 *
 * @example
 * ```typescript
 * R.symmetricDifference([1,2,3,4], [7,6,5,4,3]); //=> [1,2,7,6,5]
 * R.symmetricDifference([7,6,5,4,3], [1,2,3,4]); //=> [7,6,5,1,2]
 * ```
 */
export function symmetricDifference<T>(list1: readonly T[], list2: readonly T[]): T[];
export function symmetricDifference<T>(list: readonly T[]): <T>(list: readonly T[]) => T[];

/**
 * Finds the set (i.e. no duplicates) of all elements contained in the first or second list, but not both.
 * Duplication is determined according to the value returned by applying the supplied predicate to two list elements.
 *
 * @example
 * ```typescript
 * const eqA = R.eqBy(R.prop<number>('a'));
 * const l1 = [{a: 1}, {a: 2}, {a: 3}, {a: 4}];
 * const l2 = [{a: 3}, {a: 4}, {a: 5}, {a: 6}];
 * R.symmetricDifferenceWith(eqA, l1, l2); //=> [{a: 1}, {a: 2}, {a: 5}, {a: 6}]
 * ```
 */
export function symmetricDifferenceWith<T>(
    pred: (a: T, b: T) => boolean,
    list1: readonly T[],
    list2: readonly T[],
): T[];
export function symmetricDifferenceWith<T>(
    pred: (a: T, b: T) => boolean,
): _.F.Curry<(a: readonly T[], b: readonly T[]) => T[]>;

/**
 * A function that always returns `true`. Any passed in parameters are ignored.
 *
 * See also {@link F}.
 *
 * @example
 * ```typescript
 * R.T(); //=> true
 * ```
 */
export function T(...args: unknown[]): true;

/**
 * Returns all but the first element of a list or string.
 *
 * @example
 * ```typescript
 * R.tail([1, 2, 3]);  //=> [2, 3]
 * R.tail([1, 2]);     //=> [2]
 * R.tail([1]);        //=> []
 * R.tail([]);         //=> []
 *
 * R.tail('abc');  //=> 'bc'
 * R.tail('ab');   //=> 'b'
 * R.tail('a');    //=> ''
 * R.tail('');     //=> ''
 * ```
 */
export function tail(list: string): string;
export function tail<T>(list: readonly T[]): T[];

/**
 * Returns the first (at most) `n` elements of the given list, string, or transducer/transformer.
 *
 * Dispatches to the `take` method of the second argument, if present.
 *
 * See also {@link drop}.
 *
 * @example
 * ```typescript
 * R.take(1, ['foo', 'bar', 'baz']); //=> ['foo']
 * R.take(2, ['foo', 'bar', 'baz']); //=> ['foo', 'bar']
 * R.take(3, ['foo', 'bar', 'baz']); //=> ['foo', 'bar', 'baz']
 * R.take(4, ['foo', 'bar', 'baz']); //=> ['foo', 'bar', 'baz']
 * R.take(3, 'ramda');               //=> 'ram'
 *
 * const personnel = [
 *   'Dave Brubeck',
 *   'Paul Desmond',
 *   'Eugene Wright',
 *   'Joe Morello',
 *   'Gerry Mulligan',
 *   'Bob Bates',
 *   'Joe Dodge',
 *   'Ron Crotty'
 * ];
 *
 * const takeFive = R.take(5);
 * takeFive(personnel);
 * //=> ['Dave Brubeck', 'Paul Desmond', 'Eugene Wright', 'Joe Morello', 'Gerry Mulligan']
 * ```
 */
export function take<T>(n: number, xs: readonly T[]): T[];
export function take(n: number, xs: string): string;
export function take(n: number): {
    (xs: string): string;
    <T>(xs: readonly T[]): T[];
};
export function take<T>(n: number): (xs: readonly T[]) => T[];

/**
 * Returns a new list containing the last (at most) `n` elements of the given list.
 *
 * See also {@link dropLast}.
 *
 * @example
 * ```typescript
 * R.takeLast(1, ['foo', 'bar', 'baz']); //=> ['baz']
 * R.takeLast(2, ['foo', 'bar', 'baz']); //=> ['bar', 'baz']
 * R.takeLast(3, ['foo', 'bar', 'baz']); //=> ['foo', 'bar', 'baz']
 * R.takeLast(4, ['foo', 'bar', 'baz']); //=> ['foo', 'bar', 'baz']
 * R.takeLast(3, 'ramda');               //=> 'mda'
 * ```
 */
export function takeLast<T>(n: number, xs: readonly T[]): T[];
export function takeLast(n: number, xs: string): string;
export function takeLast(n: number): {
    (xs: string): string;
    <T>(xs: readonly T[]): T[];
};

/**
 * Returns a new list containing the last elements of a given list,
 * passing each value to the supplied predicate function
 * and terminating when the predicate function returns a falsy value.
 * Excludes the element that caused the predicate function to fail.
 *
 * See also {@link dropLastWhile}, {@link addIndex}.
 */
export function takeLastWhile<T>(pred: (a: T) => boolean, list: readonly T[]): T[];
export function takeLastWhile<T>(pred: (a: T) => boolean): <T>(list: readonly T[]) => T[];

/**
 * Returns a new list containing the first elements of a given list,
 * passing each value to the supplied predicate function,
 * and terminating when the predicate function returns a falsy value.
 *
 * Dispatches to the `takeWhile` method of the second argument, if present.
 *
 * Acts as a transducer if a transformer is given in list position.
 *
 * See also {@link dropWhile}, {@link addIndex}, {@link transduce}.
 */
export function takeWhile<T>(fn: (x: T) => boolean, list: readonly T[]): T[];
export function takeWhile<T>(fn: (x: T) => boolean): (list: readonly T[]) => T[];

/**
 * Runs the given function with the supplied object, then returns the object.
 * Acts as a transducer if a transformer is given as second parameter.
 *
 * @example
 * ```typescript
 * const sayX = <T>(x: T) => console.log('x is ' + x);
 * R.tap(sayX, 100); //=> 100
 * // logs 'x is 100'
 * ```
 */
export function tap<T, R extends T = T>(fn: (a: T) => asserts a is R, value: T): R;
export function tap<T, R extends T = T>(fn: (a: T) => asserts a is R): (value: T) => R;
export function tap<T>(fn: (a: T) => void, value: T): T;
export function tap<T>(fn: (a: T) => void): (value: T) => T;

/**
 * Determines whether a given string matches a given regular expression.
 *
 * See also {@link match}.
 *
 * @example
 * ```typescript
 * R.test(/^x/, 'xyz'); //=> true
 * R.test(/^y/, 'xyz'); //=> false
 * ```
 */
export function test(regexp: RegExp, str: string): boolean;
export function test(regexp: RegExp): (str: string) => boolean;

/**
 * Creates a thunk out of a function.
 * A thunk delays a calculation until its result is needed,
 * providing lazy evaluation of arguments.
 *
 * See also {@link partial}, {@link partialRight}.
 *
 * @example
 * ```typescript
 * R.thunkify(R.identity)(42)(); //=> 42
 * R.thunkify((a: number, b: number) => a + b)(25, 17)(); //=> 42
 * ```
 */
export function thunkify<F extends AnyFunction>(fn: F): _.F.Curry<(...args: Parameters<F>) => () => ReturnType<F>>;

/**
 * Calls an input function `n` times,
 * returning an array containing the results of those function calls.
 *
 * `fn` is passed one argument:
 * The current value of `n`,
 * which begins at `0` and is gradually incremented to `n - 1`.
 *
 * See also {@link repeat}.
 *
 * @example
 * ```typescript
 * R.times(R.identity, 5); //=> [0, 1, 2, 3, 4]
 * ```
 */
export function times<T>(fn: (i: number) => T, n: number): T[];
export function times<T>(fn: (i: number) => T): (n: number) => T[];

/**
 * The lower case version of a string.
 *
 * See also {@link toUpper}.
 *
 * @example
 * ```typescript
 * R.toLower('XYZ'); //=> 'xyz'
 * ```
 */
export function toLower<S extends string>(str: S): Lowercase<S>;
export function toLower(str: string): string;

/**
 * Converts an object into an array of key, value arrays.
 * Only the object's own properties are used.
 * Note that the order of the output array is not guaranteed to be consistent
 * across different JS platforms.
 *
 * See also {@link toPairsIn}, {@link fromPairs}, {@link keys}, {@link values}.
 */
export function toPairs<O extends object, K extends Extract<keyof O, string | number>>(
    obj: O,
): Array<{ [key in K]: [`${key}`, O[key]] }[K]>;
export function toPairs<S>(obj: Record<string | number, S>): Array<[string, S]>;

/**
 * Converts an object into an array of key, value arrays.
 * The object's own properties and prototype properties are used.
 * Note that the order of the output array is not guaranteed to be consistent
 * across different JS platforms.
 *
 * See also {@link toPairs}.=
 *
 * @example
 * ```typescript
 * class F {
 *   x: string;
 *   y = 'Y';
 *
 *   constructor() {
 *     this.x = 'X';
 *   }
 * }
 *
 * const f = new F();
 * R.toPairsIn(f); //=> [['x','X'], ['y','Y']]
 * ```
 */
export function toPairsIn<O extends object, K extends Extract<keyof O, string | number>>(
    obj: O,
): Array<{ [key in K]: [`${key}`, O[key]] }[K]>;
export function toPairsIn<S>(obj: Record<string | number, S>): Array<[string, S]>;

/**
 * Returns the string representation of the given value.
 * `eval`'ing the output should result in a value equivalent to the input value.
 * Many of the built-in `toString` methods do not satisfy this requirement.
 *
 * If the given value is an `Object` with a toString method other than `Object.prototype.toString`,
 * that method is invoked with no arguments to produce the return value.
 * This means user-defined constructor functions can provide a suitable `toString` method.
 *
 * @example
 * ```typescript
 * class Point {
 *   constructor(public x: number, public y: number) {}
 *
 *   toString() {
 *       return 'new Point(' + this.x + ', ' + this.y + ')';
 *   }
 * }
 *
 * R.toString(new Point(1, 2)); //=> 'new Point(1, 2)'
 * R.toString(42); //=> '42'
 * R.toString('abc'); //=> '"abc"'
 * R.toString([1, 2, 3]); //=> '[1, 2, 3]'
 * R.toString({foo: 1, bar: 2, baz: 3}); //=> '{"bar": 2, "baz": 3, "foo": 1}'
 * R.toString(new Date('2001-02-03T04:05:06Z')); //=> 'new Date("2001-02-03T04:05:06.000Z")'
 * ```
 */
export function toString(val: unknown): string;

/**
 * The upper case version of a string.
 *
 * See also {@link toLower}.
 *
 * @example
 * ```typescript
 * R.toUpper('abc'); //=> 'ABC'
 * ```
 */
export function toUpper<S extends string>(str: S): Uppercase<S>;
export function toUpper(str: string): string;

/**
 * Initializes a transducer using supplied iterator function.
 * Returns a single item by iterating through the list,
 * successively calling the transformed iterator function
 * and passing it an accumulator value and the current value from the array,
 * and then passing the result to the next call.
 *
 * The iterator function receives two values: `(acc, value)`.
 * It will be wrapped as a transformer to initialize the transducer.
 * A transformer can be passed directly in place of an iterator function.
 * In both cases, iteration may be stopped early with the `R.reduced` function.
 *
 * A transducer is a function that accepts a transformer and returns a transformer and can be composed directly.
 *
 * The accumulator can also be a transformer object that provides:
 * - A 2-arity iterator function, which is passed directly to reduce.
 * - A 0-arity initial value function, which is used to provide the initial accumulator.
 * This is ignored by `R.transduce`.
 * - A 1-arity result extraction function, which is used to convert the final accumulator into the return type.
 *
 * The iteration is performed with `R.reduce` after initializing the transducer.
 *
 * See also {@link reduce}, {@link reduced}, {@link into}.
 *
 * @example
 * ```typescript
 * const numbers = [1, 2, 3, 4];
 * const transducer = R.compose(R.map(R.add(1)), R.take<number>(2));
 * R.transduce(transducer, R.flip<number, number[], number[]>(R.append), [], numbers); //=> [2, 3]
 *
 * const isOdd = (x: number) => x % 2 !== 0;
 * const firstOddTransducer = R.compose(R.filter(isOdd), R.take(1));
 * R.transduce(firstOddTransducer, R.flip<number, number[], number[]>(R.append), [], R.range(0, 100)); //=> [1]
 * ```
 */
export function transduce<T, U, V>(
    xf: (arg: readonly T[]) => U[],
    fn: (acc: V, val: U) => V,
    acc: V,
    list: readonly T[],
): V;
export function transduce<T, U, V>(
    xf: (arg: readonly T[]) => U[],
): (fn: (acc: V, val: U) => V, acc: V, list: readonly T[]) => V;
export function transduce<T, U, V>(
    xf: (arg: readonly T[]) => U[],
    fn: (acc: V, val: U) => V,
): (acc: readonly T[], list: readonly T[]) => V;
export function transduce<T, U, V>(
    xf: (arg: readonly T[]) => U[],
    fn: (acc: V, val: U) => V,
    acc: readonly T[],
): (list: readonly T[]) => V;

/**
 * Transposes the rows and columns of a 2D list.
 * When passed a list of `n` lists of length `x`,
 * returns a list of `x` lists of length `n`.
 *
 * @example
 * ```typescript
 * R.transpose([[1, 'a'], [2, 'b'], [3, 'c']]) //=> [[1, 2, 3], ['a', 'b', 'c']]
 * R.transpose<string | number>([[1, 2, 3], ['a', 'b', 'c']]) //=> [[1, 'a'], [2, 'b'], [3, 'c']]
 *
 * // If some of the rows are shorter than the following rows, their elements are skipped:
 * R.transpose([[10, 11], [20], [], [30, 31, 32]]) //=> [[10, 20, 30], [11, 31], [32]]
 * ```
 */
export function transpose<T>(list: readonly T[][]): T[][];

/**
 * Maps an `Applicative`-returning function over a `Traversable`,
 * then uses `R.sequence` to transform the resulting `Traversable` of `Applicative`
 * into an `Applicative` of `Traversable`.
 *
 * Dispatches to the `traverse` method of the third argument, if present.
 *
 * See also {@link sequence}.
 *
 * @example
 * ```typescript
 * // Returns `[]` if the given divisor is `0`
 * const safeDiv = (n: number) => (d: number) => d === 0 ? [] : Array.of(n / d)
 *
 * R.traverse(Array.of, safeDiv(10), [2, 4, 5]); //=> [[5, 2.5, 2]]
 * R.traverse(Array.of, safeDiv(10), [2, 0, 5]); //=> []
 * ```
 */
export function traverse<A, B>(of: (a: B) => B[], fn: (t: A) => B[], list: readonly A[]): B[][];
export function traverse<A, B>(of: (a: B) => B[], fn: (t: A) => B[]): (list: readonly A[]) => B[][];
export function traverse<A, B>(of: (a: B) => B[]): (fn: (t: A) => B[], list: readonly A[]) => B[][];

/**
 * Removes (strips) whitespace from both ends of the string.
 *
 * @example
 * ```typescript
 * R.trim('   xyz  '); //=> 'xyz'
 * R.map(R.trim, R.split(',', 'x, y, z')); //=> ['x', 'y', 'z']
 * ```
 */
export function trim(str: string): string;

/**
 * `R.tryCatch` takes two functions, a `tryer` and a `catcher`.
 * The returned function evaluates the `tryer`;
 * if it does not throw, it simply returns the result.
 * If the `tryer` does throw,
 * the returned function evaluates the `catcher` function and returns its result.
 *
 * @note For effective composition with this function,
 * both the `tryer` and `catcher` functions must return the same type of results.
 *
 * @example
 * ```typescript
 * R.tryCatch(R.prop('x'), R.F)({ x: true }); //=> true
 * R.tryCatch((_s: string) => { throw 'foo' }, R.always('caught'))('bar') //=> 'caught'
 * // Don't do this, it's just an example
 * R.tryCatch(R.times(R.identity), R.always([]))('s' as never) //=> []
 * R.tryCatch((_s: string) => { throw 'this is not a valid value' }, (err, value)=>({ error: err,  value }))('bar')
 * //=> {'error': 'this is not a valid value', 'value': 'bar'}
 * ```
 */
export function tryCatch<F extends AnyFunction, RE = ReturnType<F>, E = unknown>(
    tryer: F,
    catcher: (error: E, ...args: _.F.Parameters<F>) => RE,
): F | (() => RE);
export function tryCatch<F extends AnyFunction>(
    tryer: F,
): <RE = ReturnType<F>, E = unknown>(catcher: (error: E, ...args: _.F.Parameters<F>) => RE) => F | (() => RE);

/**
 * Gives a single-word string description of the (native) type of a value,
 * returning such answers as `'Object'`, `'Number'`, `'Array'`, or `'Null'`.
 * Does not attempt to distinguish user `Object` types any further,
 * reporting them all as `'Object'`.
 *
 * Uses `Object.prototype.toString` internally for values other than `null` and `undefined`.
 *
 * @example
 * ```typescript
 * R.type({}); //=> "Object"
 * R.type(1); //=> "Number"
 * R.type(false); //=> "Boolean"
 * R.type('s'); //=> "String"
 * R.type(null); //=> "Null"
 * R.type([]); //=> "Array"
 * R.type(/[A-z]/); //=> "RegExp"
 * R.type(() => {}); //=> "Function"
 * R.type(undefined); //=> "Undefined"
 * ```
 */
export function type(
    val: any,
):
    | 'Object'
    | 'Number'
    | 'Boolean'
    | 'String'
    | 'Null'
    | 'Array'
    | 'RegExp'
    | 'Function'
    | 'Undefined'
    | 'Symbol'
    | 'Error';

/**
 * Takes a function `fn`, which takes a single array argument, and returns a function which:
 * - takes any number of positional arguments;
 * - passes these arguments to fn as an array; and
 * - returns the result.
 *
 * In other words, `R.unapply` derives a variadic function from a function which takes an array.
 * `R.unapply` is the inverse of `R.apply`.
 *
 * See also {@link apply}.
 *
 * @example
 * ```typescript
 * R.unapply(JSON.stringify)(1, 2, 3); //=> '[1,2,3]'
 * ```
 */
export function unapply<T>(fn: (args: any[]) => T): (...args: unknown[]) => T;

/**
 * Wraps a function of any arity (including nullary) in a function that accepts exactly 1 parameter.
 * Any extraneous parameters will not be passed to the supplied function.
 *
 * See also {@link binary}, {@link nAry}.
 *
 * @example
 * ```typescript
 * const takesTwoArgs = <T, U>(a: T, b: U) => [a, b];
 * takesTwoArgs.length; //=> 2
 * takesTwoArgs(1, 2); //=> [1, 2]
 *
 * const takesOneArg = R.unary(takesTwoArgs);
 * takesOneArg.length; //=> 1
 * // Only 1 argument is passed to the wrapped function
 * takesOneArg(1); //=> [1, undefined]
 * ```
 */
export function unary<T, R>(fn: (a: T, ...args: any[]) => R): (a: T) => R;

/**
 * Returns a function of arity n from a (manually) curried function.
 *
 * @note The returned function is actually a ramda style curryied function,
 * which can accept one or more arguments in each function calling.
 *
 * @example
 * ```typescript
 * const addFour = (a: number) => (b: number) => (c: number) => (d: number) => a + b + c + d;
 *
 * const uncurriedAddFour = R.uncurryN<number>(4, addFour);
 * uncurriedAddFour(1, 2, 3, 4); //=> 10
 * ```
 */
export function uncurryN<T>(len: number, fn: (a: any) => any): (...args: unknown[]) => T;
export function uncurryN<T>(len: number): (fn: (a: any) => any) => (...args: unknown[]) => T;

/**
 * Builds a list from a seed value.
 * Accepts an iterator function, which returns either a falsy value to stop iteration
 * or an array of length 2 containing the value to add to the resulting list
 * and the seed to be used in the next call to the iterator function.
 *
 * @example
 * ```typescript
 * const f = (n: number) => n > 50 ? false : [-n, n + 10] as const;
 * R.unfold(f, 10); //=> [-10, -20, -30, -40, -50]
 * ```
 */
export function unfold<T, TResult>(fn: (seed: T) => [TResult, T] | false, seed: T): TResult[];
export function unfold<T, TResult>(fn: (seed: T) => [TResult, T] | false): (seed: T) => TResult[];

/**
 * Combines two lists into a set (i.e. no duplicates) composed of the elements of each list.
 *
 * @example
 * ```typescript
 * R.union([1, 2, 3], [2, 3, 4]); //=> [1, 2, 3, 4]
 * ```
 */
export function union<T>(as: readonly T[], bs: readonly T[]): T[];
export function union<T>(as: readonly T[]): (bs: readonly T[]) => T[];

/**
 * Combines two lists into a set (i.e. no duplicates) composed of the elements of each list.
 * Duplication is determined according to the value returned
 * by applying the supplied predicate to two list elements.
 * If an element exists in both lists,
 * the first element from the first list will be used.
 *
 * @example
 * ```typescript
 * const l1 = [{a: 1}, {a: 2}];
 * const l2 = [{a: 1}, {a: 4}];
 * R.unionWith(R.eqBy(R.prop('a')), l1, l2); //=> [{a: 1}, {a: 2}, {a: 4}]
 * ```
 */
export function unionWith<T>(pred: (a: T, b: T) => boolean, list1: readonly T[], list2: readonly T[]): T[];
export function unionWith<T>(pred: (a: T, b: T) => boolean): _.F.Curry<(a: readonly T[], b: readonly T[]) => T[]>;

/**
 * Returns a new list containing only one copy of each element in the original list.
 *
 * @example
 * ```typescript
 * R.uniq([1, 1, 2, 1]); //=> [1, 2]
 * R.uniq([1, '1']);     //=> [1, '1']
 * R.uniq([[42], [42]]); //=> [[42]]
 * ```
 */
export function uniq<T>(list: readonly T[]): T[];

/**
 * Returns a new list containing only one copy of each element in the original list,
 * based upon the value returned by applying the supplied function to each list element.
 * Prefers the first item if the supplied function produces the same value on two items.
 * `R.equals` is used for comparison.
 *
 * @example
 * ```typescript
 * R.uniqBy(Math.abs, [-1, -5, 2, 10, 1, 2]); //=> [-1, -5, 2, 10]
 * ```
 */
export function uniqBy<T, U>(fn: (a: T) => U, list: readonly T[]): T[];
export function uniqBy<T, U>(fn: (a: T) => U): (list: readonly T[]) => T[];

/**
 * Returns a new list containing only one copy of each element in the original list,
 * based upon the value returned by applying the supplied predicate to two list elements.
 * Prefers the first item if two items compare equal based on the predicate.
 *
 * Acts as a transducer if a transformer is given in list position.
 *
 * See also {@link transduce}.
 *
 * @example
 * ```typescript
 * const strEq = R.eqBy(String);
 * R.uniqWith(strEq)([1, '1', 2, 1]); //=> [1, 2]
 * R.uniqWith(strEq)([{}, {}]);       //=> [{}]
 * R.uniqWith(strEq)([1, '1', 1]);    //=> [1]
 * R.uniqWith(strEq)(['1', 1, 1]);    //=> ['1']
 * ```
 */
export function uniqWith<T, U>(pred: (x: T, y: T) => boolean, list: readonly T[]): T[];
export function uniqWith<T, U>(pred: (x: T, y: T) => boolean): (list: readonly T[]) => T[];

/**
 * Tests the final argument by passing it to the given predicate function.
 * If the predicate is not satisfied,
 * the function will return the result of calling the `whenFalseFn` function with the same argument.
 * If the predicate is satisfied, the argument is returned as is.
 *
 * See also {@link ifElse}, {@link when}, {@link cond}.
 *
 * @example
 * ```typescript
 * let safeInc = R.unless<number | null | undefined, null | undefined>(R.isNil, R.inc);
 * safeInc(null); //=> null
 * safeInc(1); //=> 2
 * ```
 */
export function unless<T, U>(pred: (a: T) => boolean, whenFalseFn: (a: T) => U, a: T): T | U;
export function unless<T, U>(pred: (a: T) => boolean, whenFalseFn: (a: T) => U): (a: T) => T | U;

/**
 * Shorthand for `R.chain(R.identity)`,
 * which removes one level of nesting from any `Chain`.
 *
 * See also {@link flatten}, {@link chain}.
 *
 * @example
 * ```typescript
 * R.unnest([1, [2], [[3]]]); //=> [1, 2, [3]]
 * R.unnest([[1, 2], [3, 4], [5, 6]]); //=> [1, 2, 3, 4, 5, 6]
 * ```
 */
export function unnest<T extends readonly any[]>(list: T): _.T.UnNest<T>;

/**
 * Takes a predicate, a transformation function, and an initial value,
 * and returns a value of the same type as the initial value.
 * It does so by applying the transformation until the predicate is satisfied,
 * at which point it returns the satisfactory value.
 *
 * @example
 * ```typescript
 * R.until(R.gt(R.__, 100), R.multiply(2))(1) // => 128
 * ```
 */
export function until<T, U>(pred: (val: T) => boolean, fn: (val: T) => U, init: U): U;
export function until<T, U>(pred: (val: T) => boolean, fn: (val: T) => U): (init: U) => U;

/**
 * Returns a new copy of the array with the element at the provided index replaced with the given value.
 *
 * See also {@link adjust}.
 *
 * @example
 * ```typescript
 * R.update(1, '_', ['a', 'b', 'c']);      //=> ['a', '_', 'c']
 * R.update(-1, '_', ['a', 'b', 'c']);     //=> ['a', 'b', '_']
 * ```
 */
export function update<T>(index: number, value: T, list: readonly T[]): T[];
export function update<T>(index: number, value: T): (list: readonly T[]) => T[];

/**
 * Accepts a function fn and a list of transformer functions and returns a new curried function.
 * When the new function is invoked,
 * it calls the function fn with parameters
 * consisting of the result of calling each supplied handler on successive arguments to the new function.
 *
 * If more arguments are passed to the returned function than transformer functions,
 * those arguments are passed directly to fn as additional parameters.
 * If you expect additional arguments that don't need to be transformed,
 * although you can ignore them,
 * it's best to pass an identity function
 * so that the new function reports the correct arity.
 *
 * See also {@link converge}.
 *
 * @example
 * ```typescript
 * R.useWith(Math.pow, [(n: number) => n, (n: number) => n])(3, 4); //=> 81
 * R.useWith(Math.pow, [(n: number) => n, (n: number) => n])(3)(4); //=> 81
 * R.useWith(Math.pow, [R.dec, R.inc])(3, 4); //=> 32
 * R.useWith(Math.pow, [R.dec, R.inc])(3)(4); //=> 32
 * ```
 */
export function useWith<
    TArg1,
    TR1,
    TArg2,
    TR2,
    TArg3,
    TR3,
    TArg4,
    TR4,
    TArg5,
    TR5,
    TArg6,
    TR6,
    TArg7,
    TR7,
    TResult,
    RestFunctions extends AnyFunction[],
    TArgs extends [TArg1, TArg2, TArg3, TArg4, TArg5, TArg6, TArg7, ...InputTypesOfFns<RestFunctions>],
>(
    fn: (...args: [TR1, TR2, TR3, TR4, TR5, TR6, TR7, ...ReturnTypesOfFns<RestFunctions>]) => TResult,
    transformers: [
        (arg: TArg1) => TR1,
        (arg: TArg2) => TR2,
        (arg: TArg3) => TR3,
        (arg: TArg4) => TR4,
        (arg: TArg5) => TR5,
        (arg: TArg6) => TR6,
        (arg: TArg7) => TR7,
        ...RestFunctions,
    ],
): (...args: TArgs) => TResult;
export function useWith<TArg1, TR1, TArg2, TR2, TArg3, TR3, TArg4, TR4, TArg5, TR5, TArg6, TR6, TArg7, TR7, TResult>(
    fn: (...args: [TR1, TR2, TR3, TR4, TR5, TR6, TR7] & { length: 7 }) => TResult,
    transformers: [
        (arg: TArg1) => TR1,
        (arg: TArg2) => TR2,
        (arg: TArg3) => TR3,
        (arg: TArg4) => TR4,
        (arg: TArg5) => TR5,
        (arg: TArg6) => TR6,
        (arg: TArg7) => TR7,
    ],
): (...args: [TArg1, TArg2, TArg3, TArg4, TArg5, TArg7]) => TResult;
export function useWith<TArg1, TR1, TArg2, TR2, TArg3, TR3, TArg4, TR4, TArg5, TR5, TArg6, TR6, TResult>(
    fn: (...args: [TR1, TR2, TR3, TR4, TR5, TR6] & { length: 6 }) => TResult,
    transformers: [
        (arg: TArg1) => TR1,
        (arg: TArg2) => TR2,
        (arg: TArg3) => TR3,
        (arg: TArg4) => TR4,
        (arg: TArg5) => TR5,
        (arg: TArg6) => TR6,
    ],
): (...args: [TArg1, TArg2, TArg3, TArg4, TArg5, TArg6]) => TResult;
export function useWith<TArg1, TR1, TArg2, TR2, TArg3, TR3, TArg4, TR4, TArg5, TR5, TResult>(
    fn: (...args: [TR1, TR2, TR3, TR4, TR5] & { length: 5 }) => TResult,
    transformers: [
        (arg: TArg1) => TR1,
        (arg: TArg2) => TR2,
        (arg: TArg3) => TR3,
        (arg: TArg4) => TR4,
        (arg: TArg5) => TR5,
    ],
): (...args: [TArg1, TArg2, TArg3, TArg4, TArg5]) => TResult;
export function useWith<TArg1, TR1, TArg2, TR2, TArg3, TR3, TArg4, TR4, TResult>(
    fn: (...args: [TR1, TR2, TR3, TR4] & { length: 4 }) => TResult,
    transformers: [(arg: TArg1) => TR1, (arg: TArg2) => TR2, (arg: TArg3) => TR3, (arg: TArg4) => TR4],
): (...args: [TArg1, TArg2, TArg3, TArg4]) => TResult;
export function useWith<TArg1, TR1, TArg2, TR2, TArg3, TR3, TResult>(
    fn: (...args: [TR1, TR2, TR3] & { length: 3 }) => TResult,
    transformers: [(arg: TArg1) => TR1, (arg: TArg2) => TR2, (arg: TArg3) => TR3],
): (...args: [TArg1, TArg2, TArg3]) => TResult;
export function useWith<TArg1, TR1, TArg2, TR2, TResult>(
    fn: (...args: [TR1, TR2] & { length: 2 }) => TResult,
    transformers: [(arg: TArg1) => TR1, (arg: TArg2) => TR2],
): (...args: [TArg1, TArg2]) => TResult;
export function useWith<TArg1, TR1, TResult>(
    fn: (...args: [TR1]) => TResult,
    transformers: [(arg: TArg1) => TR1],
): (...args: [TArg1]) => TResult;

/**
 * Returns a list of all the enumerable own properties of the supplied object.
 *
 * @note The order of the output array is not guaranteed across different JS platforms.
 *
 * See also {@link valuesIn}, {@link keys}, {@link toPairs}.
 *
 * @example
 * ```typescript
 * R.values({a: 1, b: 2, c: 3}); //=> [1, 2, 3]
 * ```
 */
export function values<T extends object, K extends keyof T>(obj: T): Array<T[K] | ValueOfUnion<T>>;

/**
 * Returns a list of all the properties, including prototype properties, of the supplied
 * object. Note that the order of the output array is not guaranteed to be consistent across different JS platforms.
 *
 * See also {@link values}, {@link keysIn}.
 *
 * @example
 * ```typescript
 * lass F {
 *   x: string;
 *   y = 'Y';
 *
 *   constructor() {
 *     this.x = 'X';
 *   }
 * }
 *
 * const f = new F();
 * R.valuesIn(f); //=> ['X', 'Y']
 * ```
 */
export function valuesIn<T>(obj: any): T[];

/**
 * Returns a "view" of the given data structure, determined by the given lens.
 * The lens's focus determines which portion of the data structure is visible.
 *
 * See also {@link set}, {@link over}, {@link lens}, {@link lensIndex}, {@link lensProp}, {@link lensPath}.
 *
 * @example
 * ```typescript
 * const xLens = R.lensProp('x');
 *
 * const a = {x: 1, y: 2};
 * R.view(xLens, a);  //=> 1
 * const b = {x: 4, y: 2};
 * R.view(xLens, b);  //=> 4
 * ```
 */
export function view<S, A>(lens: Lens<S, A>): (obj: S) => A;
export function view<S, A>(lens: Lens<S, A>, obj: S): A;

/**
 * Tests the final argument by passing it to the given predicate function.
 * If the predicate is satisfied,
 * the function will return the result of calling the `whenTrueFn` function with the same argument.
 * If the predicate is not satisfied, the argument is returned as is.
 *
 * See also {@link ifElse}, {@link unless}, {@link cond}.
 *
 * @example
 * ```typescript
 * // truncate :: String -> String
 * const truncate = R.when(
 *   R.propSatisfies(R.gt(R.__, 10), 'length'),
 *   R.pipe(R.take(10), R.append('…'), R.join(''))
 * );
 * truncate('12345'.split(''));         //=> '12345'
 * truncate('0123456789ABC'.split('')); //=> '0123456789…'
 * ```
 */
export function when<T, U extends T, V>(pred: (a: T) => a is U, whenTrueFn: (a: U) => V, a: T): T | V;
export function when<T, U>(pred: (a: T) => boolean, whenTrueFn: (a: T) => U, a: T): T | U;
export function when<T, U extends T, V>(pred: (a: T) => a is U, whenTrueFn: (a: U) => V): (a: T) => T | V;
export function when<T, U>(pred: (a: T) => boolean, whenTrueFn: (a: T) => U): (a: T) => T | U;

/**
 * Takes a spec object and a test object and returns true if the test satisfies the spec.
 * Any property on the spec that is not a function
 * is interpreted as an equality relation.
 *
 * If the spec has a property mapped to a function,
 * then `where` evaluates the function,
 * passing in the test object's value for the property in question,
 * as well as the whole test object.
 *
 * `R.where` is well suited to declaratively expressing constraints for other functions,
 * e.g., `R.filter`, `R.find`, `R.pickWith`, etc.
 *
 * Seee also {@link propSatisfies}, {@link whereEq}.
 *
 * @example
 * ```typescript
 * // pred :: Object -> Boolean
 * const pred = R.where({
 *   a: R.equals('foo'),
 *   b: R.complement(R.equals('bar')),
 *   x: R.gt(R.__, 10),
 *   y: R.lt(R.__, 20)
 * });
 *
 * pred({a: 'foo', b: 'xxx', x: 11, y: 19}); //=> true
 * pred({a: 'xxx', b: 'xxx', x: 11, y: 19}); //=> false
 * pred({a: 'foo', b: 'bar', x: 11, y: 19}); //=> false
 * pred({a: 'foo', b: 'xxx', x: 10, y: 19}); //=> false
 * pred({a: 'foo', b: 'xxx', x: 11, y: 20}); //=> false
 * ```
 */
export function where<T, U>(spec: T, testObj: U): boolean;
export function where<T>(spec: T): <U>(testObj: U) => boolean;
export function where<ObjFunc2, U>(spec: ObjFunc2, testObj: U): boolean;
export function where<ObjFunc2>(spec: ObjFunc2): <U>(testObj: U) => boolean;

/**
 * Takes a spec object and a test object; returns `true` if the test satisfies the spec, `false` otherwise.
 * An object satisfies the spec if, for each of the spec's own properties,
 * accessing that property of the object gives the same value (in `R.eq` terms)
 * as accessing that property of the spec.
 *
 * `R.whereEq` is a specialization of `R.where`.
 *
 * See also {@link propEq}, {@link where}.
 *
 * @example
 * ```typescript
 * // pred :: Object -> Boolean
 * const pred = R.whereEq({a: 1, b: 2});
 *
 * pred({a: 1});              //=> false
 * pred({a: 1, b: 2});        //=> true
 * pred({a: 1, b: 2, c: 3});  //=> true
 * pred({a: 1, b: 1});        //=> false
 * ```
 */
export function whereEq<T, U>(spec: T, obj: U): boolean;
export function whereEq<T>(spec: T): <U>(obj: U) => boolean;

/**
 * Returns a new list without values in the first argument.
 * `R.equals` is used to determine equality.
 * Acts as a transducer if a transformer is given in list position.
 *
 * See also {@link transduce}, {@link difference}, {@link remove}.
 *
 * @example
 * ```typescript
 * R.without([1, 2], [1, 2, 1, 3, 4]); //=> [3, 4]
 * ```
 */
export function without<T>(list1: readonly unknown[], list2: readonly T[]): T[];
export function without<T>(list1: readonly T[] | readonly unknown[]): (list2: readonly T[]) => T[];

/**
 * Exclusive disjunction logical operation.
 * Returns `true` if one of the arguments is truthy and the other is falsy.
 * Otherwise, it returns `false`.
 *
 * See also {@link or}, {@link and}.
 *
 * @example
 * ```typescript
 * R.xor(true, true); //=> false
 * R.xor(true, false); //=> true
 * R.xor(false, true); //=> true
 * R.xor(false, false); //=> false
 * ```
 */
export function xor(a: any, b: any): boolean;
export function xor(a: any): (b: any) => boolean;

/**
 * Creates a new list out of the two supplied by creating each possible pair from the lists
 *
 * Short for cross product.
 *
 * @example
 * ```typescript
 * R.xprod([1, 2], ['a', 'b']); //=> [[1, 'a'], [1, 'b'], [2, 'a'], [2, 'b']]
 * ```
 */
export function xprod<K, V>(as: readonly K[], bs: readonly V[]): Array<KeyValuePair<K, V>>;
export function xprod<K>(as: readonly K[]): <V>(bs: readonly V[]) => Array<KeyValuePair<K, V>>;

/**
 * Creates a new list out of the two supplied
 * by pairing up equally-positioned items from both lists.
 * The returned list is truncated
 * to the length of the shorter of the two input lists.
 *
 * @note `R.zip` is equivalent to `R.zipWith((a, b) => [a, b] as const)`.
 *
 * @example
 * ```typescript
 * R.zip([1, 2, 3], ['a', 'b', 'c']); //=> [[1, 'a'], [2, 'b'], [3, 'c']]
 * ```
 */
export function zip<K, V>(list1: readonly K[], list2: readonly V[]): Array<KeyValuePair<K, V>>;
export function zip<K>(list1: readonly K[]): <V>(list2: readonly V[]) => Array<KeyValuePair<K, V>>;

/**
 * Creates a new object out of a list of keys and a list of values.
 * Key/value pairing is truncated to the length of the shorter of the two lists.
 *
 * @note `R.zipObj` is equivalent to `R.pipe(R.zip, R.fromPairs)`.
 *
 * @example
 * ```typescript
 * R.zipObj(['a', 'b', 'c'], [1, 2, 3]); //=> {a: 1, b: 2, c: 3}
 * ```
 */
// TODO: Dictionary<T> as a return value is to specific, any seems to loose
export function zipObj<T, K extends string>(keys: readonly K[], values: readonly T[]): { [P in K]: T };
export function zipObj<K extends string>(keys: readonly K[]): <T>(values: readonly T[]) => { [P in K]: T };
export function zipObj<T, K extends number>(keys: readonly K[], values: readonly T[]): { [P in K]: T };
export function zipObj<K extends number>(keys: readonly K[]): <T>(values: readonly T[]) => { [P in K]: T };

/**
 * Creates a new list out of the two supplied
 * by applying the function to each equally-positioned pair in the lists.
 *
 * @example
 * ```typescript
 * const f = (x: number, y: string) => [x, y] as const;
 * R.zipWith(f, [1, 2, 3], ['a', 'b', 'c']);
 * //=> [f(1, 'a'), f(2, 'b'), f(3, 'c')]
 * ```
 */
export function zipWith<T, U, TResult>(
    fn: (x: T, y: U) => TResult,
    list1: readonly T[],
    list2: readonly U[],
): TResult[];
export function zipWith<T, U, TResult>(
    fn: (x: T, y: U) => TResult,
    list1: readonly T[],
): (list2: readonly U[]) => TResult[];
export function zipWith<T, U, TResult>(
    fn: (x: T, y: U) => TResult,
): (list1: readonly T[], list2: readonly U[]) => TResult[];

/**
 * Creates a copy of the passed object by applying an fn function to the given prop property.
 * The function will not be invoked, and the object will not change if its corresponding property does not exist in the object.
 * All non-primitive properties are copied to the new object by reference.
 *
 * @example
 * ```typescript
 * const person = {name: 'James', age: 20, pets: ['dog', 'cat']};
 * R.modify('age', R.add(1), person); //=> {name: 'James', age: 21, pets: ['dog', 'cat']}
 * R.modify('pets', R.append('turtle'), person); //=> {name: 'James', age: 20, pets: ['dog', 'cat', 'turtle']}
 * ```
 */
export function modify<T extends object, K extends keyof T, P>(
    prop: K,
    fn: (a: T[K]) => P,
    obj: T,
): Omit<T, K> & Record<K, P>;
export function modify<K extends string, A, P>(
    prop: K,
    fn: (a: A) => P,
): <T extends Record<K, A>>(target: T) => Omit<T, K> & Record<K, P>;

export as namespace R;