radio/libjs/utils/subscribable.js

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2018-08-04 21:46:25 +00:00
"use strict";
var Class = require("./class");
var Subscribable = Class.inherit({
"className": "Subscribable",
"constructor": function() {
Class.fn.constructor.call(this);
this._events = Object.create(null);
},
"destructor": function() {
this.off();
Class.fn.destructor.call(this);
},
"on": function(name, handler, context) {
var handlers = this._events[name];
if (typeof name !== "string") {
throw new Error("Name of event is mandatory");
}
if (!(handler instanceof Function)) {
throw new Error("Handler of event is mandatory");
}
if (!handlers) {
handlers = [];
this._events[name] = handlers;
}
handlers.push({
handler: handler,
context: context || this,
once: false
});
},
"one": function(name) {
Subscribable.fn.on.apply(this, arguments);
this._events[name][this._events[name].length - 1].once = true;
},
"off": function(name, handler, context) {
if (typeof name === "string") {
if (this._events[name]) {
if (handler instanceof Function) {
var handlers = this._events[name];
for (var i = handlers.length - 1; i >= 0 ; --i) {
if (handlers[i].handler === handler) {
if (context) {
if (handlers[i].context === context) {
handlers.splice(i, 1);
}
} else {
handlers.splice(i, 1);
}
}
}
} else {
delete this._events[name];
}
}
} else {
this._events = Object.create(null);
}
},
"trigger": function() {
var args = [].slice.call(arguments);
if (args.length === 0) {
throw new Error("Name of event is mandatory");
}
var answer = false;
var name = args.shift();
var handlers = this._events[name];
if (handlers) {
for (var i = 0; i < handlers.length; ++i) {
var handle = handlers[i];
answer = handle.handler.apply(handle.context, args);
if (handle.once) {
handlers.splice(i, 1);
--i;
}
if (answer === false) {
return false;
}
}
}
return answer;
}
});
module.exports = Subscribable;