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/*! intercom.js | https://github.com/diy/intercom.js | Apache License (v2) */
var Intercom = (function() {
// --- lib/events.js ---
var EventEmitter = function() {};
EventEmitter.createInterface = function(space) {
var methods = {};
methods.on = function(name, fn) {
if (typeof this[space] === 'undefined') {
this[space] = {};
}
if (!this[space].hasOwnProperty(name)) {
this[space][name] = [];
}
this[space][name].push(fn);
};
methods.off = function(name, fn) {
if (typeof this[space] === 'undefined') return;
if (this[space].hasOwnProperty(name)) {
util.removeItem(fn, this[space][name]);
}
};
methods.trigger = function(name) {
if (typeof this[space] !== 'undefined' && this[space].hasOwnProperty(name)) {
var args = Array.prototype.slice.call(arguments, 1);
for (var i = 0; i < this[space][name].length; i++) {
this[space][name][i].apply(this[space][name][i], args);
}
}
};
return methods;
};
var pvt = EventEmitter.createInterface('_handlers');
EventEmitter.prototype._on = pvt.on;
EventEmitter.prototype._off = pvt.off;
EventEmitter.prototype._trigger = pvt.trigger;
var pub = EventEmitter.createInterface('handlers');
EventEmitter.prototype.on = function() {
pub.on.apply(this, arguments);
Array.prototype.unshift.call(arguments, 'on');
this._trigger.apply(this, arguments);
};
EventEmitter.prototype.off = pub.off;
EventEmitter.prototype.trigger = pub.trigger;
// --- lib/localstorage.js ---
var localStorage = window.localStorage;
if (typeof localStorage === 'undefined') {
localStorage = {
getItem : function() {},
setItem : function() {},
removeItem : function() {}
};
}
// --- lib/util.js ---
var util = {};
util.guid = (function() {
var S4 = function() {
return (((1 + Math.random()) * 0x10000) | 0).toString(16).substring(1);
};
return function() {
return S4() + S4() + '-' + S4() + '-' + S4() + '-' + S4() + '-' + S4() + S4() + S4();
};
})();
util.throttle = function(delay, fn) {
var last = 0;
return function() {
var now = (new Date()).getTime();
if (now - last > delay) {
last = now;
fn.apply(this, arguments);
}
};
};
util.extend = function(a, b) {
if (typeof a === 'undefined' || !a) { a = {}; }
if (typeof b === 'object') {
for (var key in b) {
if (b.hasOwnProperty(key)) {
a[key] = b[key];
}
}
}
return a;
};
util.removeItem = function(item, array) {
for (var i = array.length - 1; i >= 0; i--) {
if (array[i] === item) {
array.splice(i, 1);
}
}
return array;
};
// --- lib/intercom.js ---
/**
* A cross-window broadcast service built on top
* of the HTML5 localStorage API. The interface
* mimic socket.io in design.
*
* @author Brian Reavis
* @constructor
*/
var Intercom = function() {
var self = this;
var now = (new Date()).getTime();
this.origin = util.guid();
this.lastMessage = now;
this.bindings = [];
this.receivedIDs = {};
this.previousValues = {};
var storageHandler = function() { self._onStorageEvent.apply(self, arguments); };
if (window.attachEvent) { document.attachEvent('onstorage', storageHandler); }
else { window.addEventListener('storage', storageHandler, false); };
};
Intercom.prototype._transaction = function(fn) {
var TIMEOUT = 1000;
var WAIT = 20;
var self = this;
var executed = false;
var listening = false;
var waitTimer = null;
var lock = function() {
if (executed) return;
var now = (new Date()).getTime();
var activeLock = parseInt(localStorage.getItem(INDEX_LOCK) || 0);
if (activeLock && now - activeLock < TIMEOUT) {
if (!listening) {
self._on('storage', lock);
listening = true;
}
waitTimer = window.setTimeout(lock, WAIT);
return;
}
executed = true;
localStorage.setItem(INDEX_LOCK, now);
fn();
unlock();
};
var unlock = function() {
if (listening) { self._off('storage', lock); }
if (waitTimer) { window.clearTimeout(waitTimer); }
localStorage.removeItem(INDEX_LOCK);
};
lock();
};
Intercom.prototype._cleanup_emit = util.throttle(100, function() {
var self = this;
this._transaction(function() {
var now = (new Date()).getTime();
var threshold = now - THRESHOLD_TTL_EMIT;
var changed = 0;
var messages = JSON.parse(localStorage.getItem(INDEX_EMIT) || '[]');
for (var i = messages.length - 1; i >= 0; i--) {
if (messages[i].timestamp < threshold) {
messages.splice(i, 1);
changed++;
}
}
if (changed > 0) {
localStorage.setItem(INDEX_EMIT, JSON.stringify(messages));
}
});
});
Intercom.prototype._cleanup_once = util.throttle(100, function() {
var self = this;
this._transaction(function() {
var timestamp, ttl, key;
var table = JSON.parse(localStorage.getItem(INDEX_ONCE) || '{}');
var now = (new Date()).getTime();
var changed = 0;
for (key in table) {
if (self._once_expired(key, table)) {
delete table[key];
changed++;
}
}
if (changed > 0) {
localStorage.setItem(INDEX_ONCE, JSON.stringify(table));
}
});
});
Intercom.prototype._once_expired = function(key, table) {
if (!table) return true;
if (!table.hasOwnProperty(key)) return true;
if (typeof table[key] !== 'object') return true;
var ttl = table[key].ttl || THRESHOLD_TTL_ONCE;
var now = (new Date()).getTime();
var timestamp = table[key].timestamp;
return timestamp < now - ttl;
};
Intercom.prototype._localStorageChanged = function(event, field) {
if (event && event.key) {
return event.key === field;
}
var currentValue = localStorage.getItem(field);
if (currentValue === this.previousValues[field]) {
return false;
}
this.previousValues[field] = currentValue;
return true;
};
Intercom.prototype._onStorageEvent = function(event) {
event = event || window.event;
var self = this;
if (this._localStorageChanged(event, INDEX_EMIT)) {
this._transaction(function() {
var now = (new Date()).getTime();
var data = localStorage.getItem(INDEX_EMIT);
var messages = JSON.parse(data || '[]');
for (var i = 0; i < messages.length; i++) {
if (messages[i].origin === self.origin) continue;
if (messages[i].timestamp < self.lastMessage) continue;
if (messages[i].id) {
if (self.receivedIDs.hasOwnProperty(messages[i].id)) continue;
self.receivedIDs[messages[i].id] = true;
}
self.trigger(messages[i].name, messages[i].payload);
}
self.lastMessage = now;
});
}
this._trigger('storage', event);
};
Intercom.prototype._emit = function(name, message, id) {
id = (typeof id === 'string' || typeof id === 'number') ? String(id) : null;
if (id && id.length) {
if (this.receivedIDs.hasOwnProperty(id)) return;
this.receivedIDs[id] = true;
}
var packet = {
id : id,
name : name,
origin : this.origin,
timestamp : (new Date()).getTime(),
payload : message
};
var self = this;
this._transaction(function() {
var data = localStorage.getItem(INDEX_EMIT) || '[]';
var delimiter = (data === '[]') ? '' : ',';
data = [data.substring(0, data.length - 1), delimiter, JSON.stringify(packet), ']'].join('');
localStorage.setItem(INDEX_EMIT, data);
self.trigger(name, message);
window.setTimeout(function() { self._cleanup_emit(); }, 50);
});
};
Intercom.prototype.bind = function(object, options) {
for (var i = 0; i < Intercom.bindings.length; i++) {
var binding = Intercom.bindings[i].factory(object, options || null, this);
if (binding) { this.bindings.push(binding); }
}
};
Intercom.prototype.emit = function(name, message) {
this._emit.apply(this, arguments);
this._trigger('emit', name, message);
};
Intercom.prototype.once = function(key, fn, ttl) {
if (!Intercom.supported) return;
var self = this;
this._transaction(function() {
var data = JSON.parse(localStorage.getItem(INDEX_ONCE) || '{}');
if (!self._once_expired(key, data)) return;
data[key] = {};
data[key].timestamp = (new Date()).getTime();
if (typeof ttl === 'number') {
data[key].ttl = ttl * 1000;
}
localStorage.setItem(INDEX_ONCE, JSON.stringify(data));
fn();
window.setTimeout(function() { self._cleanup_once(); }, 50);
});
};
util.extend(Intercom.prototype, EventEmitter.prototype);
Intercom.bindings = [];
Intercom.supported = (typeof localStorage !== 'undefined');
var INDEX_EMIT = 'intercom';
var INDEX_ONCE = 'intercom_once';
var INDEX_LOCK = 'intercom_lock';
var THRESHOLD_TTL_EMIT = 50000;
var THRESHOLD_TTL_ONCE = 1000 * 3600;
Intercom.destroy = function() {
localStorage.removeItem(INDEX_LOCK);
localStorage.removeItem(INDEX_EMIT);
localStorage.removeItem(INDEX_ONCE);
};
Intercom.getInstance = (function() {
var intercom = null;
return function() {
if (!intercom) {
intercom = new Intercom();
}
return intercom;
};
})();
// --- lib/bindings/socket.js ---
/**
* Socket.io binding for intercom.js.
*
* - When a message is received on the socket, it's emitted on intercom.
* - When a message is emitted via intercom, it's sent over the socket.
*
* @author Brian Reavis
*/
var SocketBinding = function(socket, options, intercom) {
options = util.extend({
id : null,
send : true,
receive : true
}, options);
if (options.receive) {
var watchedEvents = [];
var onEventAdded = function(name, fn) {
if (watchedEvents.indexOf(name) === -1) {
watchedEvents.push(name);
socket.on(name, function(data) {
var id = (typeof options.id === 'function') ? options.id(name, data) : null;
var emit = (typeof options.receive === 'function') ? options.receive(name, data) : true;
if (emit || typeof emit !== 'boolean') {
intercom._emit(name, data, id);
}
});
}
};
for (var name in intercom.handlers) {
for (var i = 0; i < intercom.handlers[name].length; i++) {
onEventAdded(name, intercom.handlers[name][i]);
}
}
intercom._on('on', onEventAdded);
}
if (options.send) {
intercom._on('emit', function(name, message) {
var emit = (typeof options.send === 'function') ? options.send(name, message) : true;
if (emit || typeof emit !== 'boolean') {
socket.emit(name, message);
}
});
}
};
SocketBinding.factory = function(object, options, intercom) {
if (typeof object.socket === 'undefined') { return false };
return new SocketBinding(object, options, intercom);
};
Intercom.bindings.push(SocketBinding);
return Intercom;
})();