/* ------- util functions -------
function merge (/* ...objects */) {
  var k, obj
  var res = {}
  var objs = Array.prototype.slice.call(arguments)

  for (var i = 0, l = objs.length; i < l; i++) {
    obj = objs[i]
    for (k in obj) {
      if (obj.hasOwnProperty(k)) {
        res[k] = obj[k]
      }
    }
  }
  return res
}