curry

curry.js

function curry(fn) {
  const arity = fn.length;

  return function $curry(...args) {
    if (args.length < arity) {
      return $curry.bind(null, ...args);
    }
    return fn.call(null, ...args);
  };
}

// some examples

function add(a,b,c) {
  return a + b + c;
}

function one(a) {
  return a + 1;
}

const cAdd = curry(add);
const cOne = curry(one);

console.log(cOne(1))          // 2
console.log(cAdd(3)(2)(1))   // 6
console.log(cAdd(5,6)(6))   // 17