functional programming - Currying in javascript for function with n parameters

Question

If f :: (a, b) -> c, we can define curry(f) as below:

curry(f) :: ((a, b) -> c) -> a -> b -> c

const curry = f => a => b => f(a, b);
const sum = curry((num1, num2) => num1 + num2);
console.log(sum(2)(3)); //5

How do we implement generic curry function that takes a function with n parameters?

Answer 1

If I understand correctly, I think this is the way to go using ES6:

const curry = f => {
  const nargs = f.length;
  const vargs = [];
  const curried = (...args) => vargs.push(...args) >= nargs
    ? f(...vargs.slice(0, nargs))
    : curried;

  return curried;
};

const fn2 = curry((a, b) => a + b);
const fn3 = curry((a, b, c) => a * (b + c));
const fn4 = curry((a, b, c, d) => Math.pow(a, b * (c + d)));

console.log(fn2(1)(2)); // 1 + 2
console.log(fn3(2)(3)(4)); // 2 * (3 + 4)
console.log(fn4(2)(1, 3)(4)); // 2 ^ (1 * (3 + 4))