code: function (arr) {
      var hash = {}
      var result = []
      for (var i = 0, l = arr.length; i < l; ++i) {
        if (!hash.hasOwnProperty(arr[i])) {
          hash[arr[i]] = true
          result.push(arr[i])
        }
      }
      return result
    }
docs: /*
  get unique elements of an array