third_party/polymer/v1_0/components/more-routing/params.html

   1 <!--
   2 Copyright (c) 2015 The Polymer Project Authors. All rights reserved.
   3 This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt
   4 The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt
   5 The complete set of contributors may be found at http://polymer.github.io/CONTRIBUTORS.txt
   6 Code distributed by Google as part of the polymer project is also
   7 subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
   8 -->
   9 <link rel="import" href="emitter.html">
  10
  11 <script>
  12 (function(scope) {
  13 var MoreRouting = scope.MoreRouting = scope.MoreRouting || {};
  14 MoreRouting.Params = Params;
  15
  16 /**
  17  * A collection of route parameters and their values, with nofications.
  18  *
  19  * Params prefixed by `__` are reserved.
  20  *
  21  * @param {!Array<string>} params The keys of the params being managed.
  22  * @param {Params=} parent A parent route's params to inherit.
  23  * @return {Params}
  24  */
  25 function Params(params, parent) {
  26   var model = Object.create(parent || Params.prototype);
  27   // We have a different set of listeners at every level of the hierarchy.
  28   Object.defineProperty(model, '__listeners', {value: []});
  29
  30   // We keep all state enclosed within this closure so that inheritance stays
  31   // relatively straightfoward.
  32   var state = {};
  33   _compile(model, params, state);
  34
  35   return model;
  36 }
  37 Params.prototype = Object.create(MoreRouting.Emitter);
  38
  39 // Utility
  40
  41 function _compile(model, params, state) {
  42   params.forEach(function(param) {
  43     Object.defineProperty(model, param, {
  44       get: function() {
  45         return state[param];
  46       },
  47       set: function(value) {
  48         if (state[param] === value) return;
  49         state[param] = value;
  50         model.__notify(param, value);
  51       },
  52     });
  53   });
  54 }
  55
  56 })(window);
  57 </script>