es-toolkit/docs/reference/function/curry.md

curry

Curries a function, allowing it to be called with a single argument at a time and returning a new function that takes the next argument. This process continues until all arguments have been provided, at which point the original function is called with all accumulated arguments.

Signature

function curry<R>(func: () => R): () => R;
function curry<P, R>(func: (p: P) => R): (p: P) => R;
function curry<P1, P2, R>(func: (p1: P1, p2: P2) => R): (p1: P1) => (p2: P2) => R;
function curry<P1, P2, P3, R>(func: (p1: P1, p2: P2, p3: P3) => R): (p1: P1) => (p2: P2) => (p3: P3) => R;
function curry<P1, P2, P3, P4, R>(
  func: (p1: P1, p2: P2, p3: P3, p4: P4) => R
): (p1: P1) => (p2: P2) => (p3: P3) => (p4: P4) => R;
function curry<P1, P2, P3, P4, P5, R>(
  func: (p1: P1, p2: P2, p3: P3, p4: P4, p5: P5) => R
): (p1: P1) => (p2: P2) => (p3: P3) => (p4: P4) => (p5: P5) => R;
function curry(func: (...args: any[]) => any): (...args: any[]) => any;

Parameters

• func (Function): The function to curry.

Returns

(Function): A curried function that can be called with a single argument at a time.

Examples

function sum(a: number, b: number, c: number) {
  return a + b + c;
}

const curriedSum = curry(sum);

// The parameter `a` should be given the value `10`.
const sum10 = curriedSum(10);

// The parameter `b` should be given the value `15`.
const sum25 = sum10(15);

// The parameter `c` should be given the value `5`. The function 'sum' has received all its arguments and will now return a value.
const result = sum25(5);

Lodash Compatibility

Import curry from es-toolkit/compat for full compatibility with lodash.

Signature

function curry(
  func: (...args: any[]) => any,
  arity: number = func.length,
  guard?: unknown
): ((...args: any[]) => any) & { placeholder: typeof curry.placeholder };

namespace curry {
  placeholder: symbol;
}

• curry accepts an additional numeric parameter, arity, which specifies the number of arguments the function should accept.
  • Defaults to the length property of the function. If arity is negative or NaN, it will be converted to 0. If it's a fractional number, it will be rounded down to the nearest integer.
• guard enables use as an iteratee for methods like Array#map.
• The curry.placeholder value, which defaults to a symbol, may be used as a placeholder for partially applied arguments.
• Unlike the native curry, this function allows multiple arguments to be called at once and returns a new function that accepts the remaining arguments.

Examples

import { curry } from 'es-toolkit/compat';

const abc = function (a, b, c) {
  return Array.from(arguments);
};

let curried = curry(abc);

curried(1)(2)(3);
// => [1, 2, 3]

curried(1, 2)(3);
// => [1, 2, 3]

curried(1, 2, 3);
// => [1, 2, 3]

// Curried with placeholders.
curried(1)(curry.placeholder, 3)(2);
// => [1, 2, 3]

// Curried with arity.
curried = curry(abc, 2);

curried(1)(2);
// => [1, 2]