1 2 (function(){ 3 4 Polymer('core-signals',{ 5 attached: function() { 6 signals.push(this); 7 }, 8 removed: function() { 9 var i = signals.indexOf(this); 10 if (i >= 0) { 11 signals.splice(i, 1); 12 } 13 } 14 }); 15 16 // private shared database 17 var signals = []; 18 19 // signal dispatcher 20 function notify(name, data) { 21 // convert generic-signal event to named-signal event 22 var signal = new CustomEvent('core-signal-' + name, { 23 // if signals bubble, it's easy to get confusing duplicates 24 // (1) listen on a container on behalf of local child 25 // (2) some deep child ignores the event and it bubbles 26 // up to said container 27 // (3) local child event bubbles up to container 28 // also, for performance, we avoid signals flying up the 29 // tree from all over the place 30 bubbles: false, 31 detail: data 32 }); 33 // dispatch named-signal to all 'signals' instances, 34 // only interested listeners will react 35 signals.forEach(function(s) { 36 s.dispatchEvent(signal); 37 }); 38 } 39 40 // signal listener at document 41 document.addEventListener('core-signal', function(e) { 42 notify(e.detail.name, e.detail.data); 43 }); 44 45 })(); 46
