File size: 3,334 Bytes
b3787d8 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 | 'use strict';
/*
global window,
document,
app
*/
(function() {
// check if the app itself is defined at all
if (! app) {
return console.error('[modules/events] app.js has not been loaded yet');
}
// create the module object
var eventModule = {
events: {}
};
/**
* on function.
* adds a callback to an event stack
*
* @param {string} type the event to subscribe to
* @param {function} callback the event callback to subscribe
*
* @return void
*/
eventModule.on = function(type, callback) {
// if there is no callback registered for this event yet, create an array for this event
if (! this.events.hasOwnProperty(type)) {
this.events[ type ] = [];
}
// push the event callback to the handler stack
this.events[ type ].push(callback);
};
/**
* off function.
* removes a callback from an event stack
*
* @param {string} type the event to unsubscribe from
* @param {function} callback the event callback to unsubscribe
*
* @return {boolean} whether the callback was removed or not
*/
eventModule.off = function(type, callback) {
// if the event does not exist, return false
if (! type in this.events) {
return false;
}
// if no callback to unsubscribe was given, remove all callbacks
if (typeof callback === 'undefined') {
return delete this.events[ type ];
}
// iterate over handlers, remove the callback in question
this.events[ type ] = this.events[ type ].filter(
function(item) {
if (item !== callback) {
return item;
}
}
);
return true;
};
/**
* emit function.
* calls all registered callbacks for an event
*
* @param {string} type the event to trigger callbacks for
* @param {*} [data] optional data to hand over to the callbacks
* @param {*} [context] optional context to hand over to the callbacks,
* defaults to window
*
* @return {boolean} whether the event has been fired
*/
eventModule.emit = function(type, data, context) {
// use an empty object if no data given
data = data || {};
// use window as the context if no context given
context = context || window;
// the event does not exist.
if (! this.events.hasOwnProperty(type)) {
return false;
}
// iterate over all callbacks, run them as expected
for (var i = 0; i < this.events[ type ].length; i++) {
this.events[ type ][ i ].call(context, type, data);
}
return true;
};
/**
* getEvents function.
* returns all registered events.
*
* @return {Array} the list of events
*/
eventModule.getEvents = function () {
var events = [];
for (var event in this.events) {
if (! this.events.hasOwnProperty(event)) continue;
events.push(event);
}
return events;
};
// register the module in the app
app.registerModule('events', eventModule, function() {
// register event endpoints
app.mountModuleEndpoint('on', 'events', 'on');
app.mountModuleEndpoint('off', 'events', 'off');
app.mountModuleEndpoint('emit', 'events', 'emit');
});
// return the module
return eventModule;
})();
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