JavaScript curry function that can handle partial application of any level when the function is applied.

javascript-autocurry-partial-application-of-any-level.js

curry = function (fn) {
  var numargs = fn.length;
  return createRecurser([]);
  
  function createRecurser (acc) {
    return function () {
      var args = [].slice.call(arguments);
      return recurse(acc, args);
    };
  }
  
  function recurse (acc, args) {
    var newacc = acc.concat(args);
    if (newacc.length < numargs) {
      return createRecurser(newacc);
    }
    else {
      return fn.apply(this, newacc);
    }
  }
}

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

var add2 = add(2);
var add4 = add2(2);
console.log(add(2)(2)(2)); // 6
console.log(add2(2)(3)); // 7
console.log(add2(2)(4)); // 8
console.log(add4(5)); // 9

var times = curry(function (a, b, c) {
  return a * b * c;
});

var times2 = times(2);
var times4 = times2(2);
console.log(times(2)(2)(2)); // 8
console.log(times2(2)(3)); // 12
console.log(times4(4)); // 16

console.log(times(2, 3, 4)); // 24
console.log(times(2)(3, 4)); // 24
console.log(times(2, 3)(4)); // 24
console.log(times(2)(3)(4)); // 24

And a sweet.js autocurry macro http://bit.ly/js-autocurry