functional-javascript-workshop/exercises/currying/problem.md

The basics of functional programming in JavaScript. No libraries required.

This is an example implementation of `curry3`, which curries up to 3 arguments:

```js
function curry3(fun){
  return function(one){
    return function(two){
      return function (three){
        return fun(one, two, three)
      }
    }
  }
}
```

If we were to use this implementation with this sample function:

```js
function abc(one, two, three) {
  return one/two/three
}
```

It would work like so:

```js
var curryC = curry3(abc)
var curryB = curryC(6)
var curryA = curryB(3)

console.log(curryA(2)) // => 1
```

# Task

In this challenge, we're going to implement a 'curry' function for an arbitrary number of arguments.

`curryN` will take two parameters:

* fn: The function we want to curry.
* n: Optional number of arguments to curry. If not supplied, `curryN` should use the fn's arity as the value for `n`.

## Example

```js
function add3(one, two, three) {
  return one + two + three
}

var curryC = curryN(add3)
var curryB = curryC(1)
var curryA = curryB(2)
console.log(curryA(3)) // => 6
console.log(curryA(10)) // => 13

console.log(curryN(add3)(1)(2)(3)) // => 6
```

## Conditions

* Do not use any for/while loops or `Array.prototype.forEach`.

## Hint

* You can detect the number of expected arguments to a function (it's arity) by checking a function's .length property.

## Boilerplate

```js
function curryN(fn, n) {
  // SOLUTION GOES HERE
}

module.exports = curryN
```