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1 <!-- | |
2 @license | |
3 Copyright (c) 2015 The Polymer Project Authors. All rights reserved. | |
4 This code may only be used under the BSD style license found at http://polymer.g
ithub.io/LICENSE.txt | |
5 The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt | |
6 The complete set of contributors may be found at http://polymer.github.io/CONTRI
BUTORS.txt | |
7 Code distributed by Google as part of the polymer project is also | |
8 subject to an additional IP rights grant found at http://polymer.github.io/PATEN
TS.txt | |
9 --> | |
10 <link rel="import" href="../polymer/polymer.html"> | |
11 | |
12 <script> | |
13 (function(){ | |
14 /** | |
15 `iron-signals` provides basic publish-subscribe functionality. | |
16 | |
17 Note: avoid using `iron-signals` whenever you can use | |
18 a controller (parent element) to mediate communication | |
19 instead. | |
20 | |
21 To send a signal, fire a custom event of type `iron-signal`, with | |
22 a detail object containing `name` and `data` fields. | |
23 | |
24 this.fire('iron-signal', {name: 'hello', data: null}); | |
25 | |
26 To receive a signal, listen for `iron-signal-<name>` event on a | |
27 `iron-signals` element. | |
28 | |
29 <iron-signals on-iron-signal-hello="{{helloSignal}}"> | |
30 | |
31 You can fire a signal event from anywhere, and all | |
32 `iron-signals` elements will receive the event, regardless | |
33 of where they are in DOM. | |
34 | |
35 @demo demo/index.html | |
36 */ | |
37 Polymer({ | |
38 is: 'iron-signals', | |
39 | |
40 attached: function() { | |
41 signals.push(this); | |
42 }, | |
43 detached: function() { | |
44 var i = signals.indexOf(this); | |
45 if (i >= 0) { | |
46 signals.splice(i, 1); | |
47 } | |
48 } | |
49 }); | |
50 | |
51 // private shared database | |
52 var signals = []; | |
53 | |
54 // signal dispatcher | |
55 function notify(name, data) { | |
56 // convert generic-signal event to named-signal event | |
57 var signal = new CustomEvent('iron-signal-' + name, { | |
58 // if signals bubble, it's easy to get confusing duplicates | |
59 // (1) listen on a container on behalf of local child | |
60 // (2) some deep child ignores the event and it bubbles | |
61 // up to said container | |
62 // (3) local child event bubbles up to container | |
63 // also, for performance, we avoid signals flying up the | |
64 // tree from all over the place | |
65 bubbles: false, | |
66 detail: data | |
67 }); | |
68 // dispatch named-signal to all 'signals' instances, | |
69 // only interested listeners will react | |
70 signals.forEach(function(s) { | |
71 s.dispatchEvent(signal); | |
72 }); | |
73 } | |
74 | |
75 // signal listener at document | |
76 document.addEventListener('iron-signal', function(e) { | |
77 notify(e.detail.name, e.detail.data); | |
78 }); | |
79 | |
80 })(); | |
81 </script> | |
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