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bower_components/iron-signals/iron-signals.html 2.42 KB
a1a3bc73   Luigi Serra   graphs updates
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  <!--
  @license
  Copyright (c) 2015 The Polymer Project Authors. All rights reserved.
  This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt
  The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt
  The complete set of contributors may be found at http://polymer.github.io/CONTRIBUTORS.txt
  Code distributed by Google as part of the polymer project is also
  subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
  -->
  <link rel="import" href="../polymer/polymer.html">
  
  <script>
  (function(){
  /**
  `iron-signals` provides basic publish-subscribe functionality.
  
  Note: avoid using `iron-signals` whenever you can use
  a controller (parent element) to mediate communication
  instead.
  
  To send a signal, fire a custom event of type `iron-signal`, with
  a detail object containing `name` and `data` fields.
  
      this.fire('iron-signal', {name: 'hello', data: null});
  
  To receive a signal, listen for `iron-signal-<name>` event on a
  `iron-signals` element.
  
    <iron-signals on-iron-signal-hello="{{helloSignal}}">
  
  You can fire a signal event from anywhere, and all
  `iron-signals` elements will receive the event, regardless
  of where they are in DOM.
  
  @demo demo/index.html
  */
    Polymer({
      is: 'iron-signals',
  
      attached: function() {
        signals.push(this);
      },
      detached: function() {
        var i = signals.indexOf(this);
        if (i >= 0) {
          signals.splice(i, 1);
        }
      }
    });
  
    // private shared database
    var signals = [];
  
    // signal dispatcher
    function notify(name, data) {
      // convert generic-signal event to named-signal event
      var signal = new CustomEvent('iron-signal-' + name, {
        // if signals bubble, it's easy to get confusing duplicates
        // (1) listen on a container on behalf of local child
        // (2) some deep child ignores the event and it bubbles
        //     up to said container
        // (3) local child event bubbles up to container
        // also, for performance, we avoid signals flying up the
        // tree from all over the place
        bubbles: false,
        detail: data
      });
      // dispatch named-signal to all 'signals' instances,
      // only interested listeners will react
      signals.forEach(function(s) {
        s.dispatchEvent(signal);
      });
    }
  
    // signal listener at document
    document.addEventListener('iron-signal', function(e) {
      notify(e.detail.name, e.detail.data);
    });
  
  })();
  </script>