My own implementation of curry 🍛

curry.js

// Ultimate version
const curry = (f, ...args) =>
  f.length <= args.length
    ? f(...args)
    : x => curry(f, ...args, x)

That version is not a full auto-curry.

Try this:

const curry = (fn, length = fn.length) => function curried (...args) {
  return args.length >= length ?
    fn(...args) :
    (...args2) => curried(...args, ...args2)
  ;
};

This is the version I've been using in examples:

const curry = (
  f, arr = []
) => (...args) => (
  a => a.length === f.length ?
    f(...a) :
    curry(f, a)
)([...arr, ...args]);

Awesome 😍 Thanks very much! I just noticed I need the second ...args in the recursive call to curried 😉

I see what you did there with the default param, very clever! 🤓 I was actually looking for a way to return that lambda without the function keyword, and here I have my answer 😊

Hi! I'm here because I watched again your talk about Lenses in Lambda World (again = I was there that day 😉 ). Congrats for it!
I would like to know what do you think about these concerns:

• The possibility of calling that function with more than one parameter. For example, a different arity could be passed.
• The possibility of not having unary functions because of (...argz).

Here I have another version to avoid those things: https://gist.github.com/rachelcarmena/196b9f8b1c6b078b65fb1328f09c0269

What do you think about it? Do you think that my concerns make sense?

Thanks in advance!

Hi Rachel! Thanks for the compliments, I'm glad you like the talk! ☺️ I think you are right, what about this implementation?

const curry = (f, ...args) => f.length <= args.length ? f(...args) : x => curry(f, ...args, x)

The argz thing was added by @ericelliott, I don't really remember now why to be honest 😂

Thanks @kutyel! I'd remove all the additional parameters. For example, this situation would be possible:

const sum = (a, b) => a + b;
const curriedSum = curry(sum);
const wrongCurriedSum1 = curry(sum, 2); // a function with one parameter
console.log(wrongCurriedSum1(3)); // 5
const wrongCurriedSum2 = curry(sum, 2, 3); // not a function, but 5
const wrongCurriedSum3 = curry(sum, 2, 3, 4); // not a function, but 5

Thanks again!