autocurry.js

var autoCurry = (function () {
 
  var toArray = function toArray(arr, from) {
    return Array.prototype.slice.call(arr, from || 0);
  },

  curry = function curry(fn /* variadic number of args */) {
    var args = toArray(arguments, 1);
    return function curried() {
      return fn.apply(this, args.concat(toArray(arguments)));
    };
  };

  return function autoCurry(fn, numArgs) {
    numArgs = numArgs || fn.length;
    return function autoCurried() {
      if (arguments.length < numArgs) {
        return numArgs - arguments.length > 0 ?
          autoCurry(curry.apply(this, [fn].concat(toArray(arguments))), numArgs - arguments.length) :
          curry.apply(this, [fn].concat(toArray(arguments)));
      }
      else {
        return fn.apply(this, arguments);
      }
    };
  };

}());