Created
April 20, 2016 18:24
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/** | |
* A simple "event" emitter for | |
* Dart inspired by the classical | |
* stuff used in JavaScript/ActionScript. | |
*/ | |
library dart_events; | |
class EventEmitter { | |
Map<String, List<Function>> _listeners = new Map<String, List<Function>>(); | |
EventEmitter(); | |
on(String type, Function handler) { | |
// Create the channel if it doesn't exist | |
_listeners.putIfAbsent(type, () { | |
return new List<Function>(); | |
}); | |
List<Function> listeners = _listeners[type]; | |
bool exists = listeners.contains(handler); | |
if (!exists) { | |
listeners.add(handler); | |
} | |
} | |
off(String type, Function handler) { | |
if (_listeners.containsKey(type)) { | |
List<Function> listeners = _listeners[type]; | |
int index = listeners.indexOf(handler); | |
if (index != -1) { | |
listeners.removeAt(index); | |
} | |
} | |
} | |
emit(String type, dynamic data) { | |
if (_listeners.containsKey(type)) { | |
List<Function> listeners = _listeners[type]; | |
listeners.forEach((Function item) { | |
// Getting an exception with this (2013/01/07) | |
// | |
// Exception: UnimplementedError: Function.apply not implemented | |
// Stack Trace: #0 Function.apply (dart:core-patch:729:5) | |
// Function.apply(item, ...); | |
// but I'd like to use Function.apply ... | |
item(data); | |
}); | |
} | |
} | |
Map<String, List<Function>> listeners () => _listeners; | |
} |
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