950

coffee

for x, index in [1, 2, 3]
  func = ->
  console.log index
  index++

current.js

var func, index, x, _fn, _len, _ref;
_ref = [1, 2, 3];
_fn = function(x, index) {
  func = function() {};
  console.log(index);
  return index++;
};
for (index = 0, _len = _ref.length; index < _len; index++) {
  x = _ref[index];
  _fn(x, index);
}

proposed.js

var func, index, x, _fn, _len, _ref, _ref2;
_ref = [1, 2, 3];
_fn = function(x, index) {
  func = function() {};
  console.log(index);
  return index++;
};
for (_ref2 = 0, _len = _ref.length; _ref2 < _len; _ref2++) {
  _fn(_ref[_ref2], _ref2);
}