Index: third_party/polymer/v0_8/components-chromium/iron-signals/iron-signals-extracted.js |
diff --git a/third_party/polymer/v0_8/components-chromium/iron-signals/iron-signals-extracted.js b/third_party/polymer/v0_8/components-chromium/iron-signals/iron-signals-extracted.js |
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+ |
+(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); |
+ }); |
+ |
+})(); |