how about this for two-sum

[jhanink]

var twoSum = function (nums, target) {
  var hash = {}; 
  for (var i=0;i<nums.length;i++) {
    var found = hash[nums[i]];
    if (found) {
      return [found, i+1]; 
    } else {
      hash[target-nums[i]] = i+1;
    }     
  }
  return [];
}