withObservable

Small and simple observable pattern.

• enforces event-name registration on init
• observable pattern is used to clearly distinct from EventEmitter and sometimes ambigious on-methods
• lightweight solution

Installation

npm install with-observable --save

Usage

1
2// mixin the observable behaviour:
3// myobject.observers;
4// myobject.addObserver;
5// myobject.addObserverOnce;
6// myobject.removeObserver;
7// myobject.notify;
8myObject = withObservable.call(myObject, ["event_name", "another_event"]);
9
10// register to an event
11myObject.addObserver("event_name", function () {
12	// do something
13});
14
15// register to an event once
16myObject.addObserver("event_name", function () {
17	// do something, will never be called again
18});
19
20// prioritize an event listener (gets executed first)
21myObject.addObserver("event_name", function () {
22	// do something
23}, true);
24
25// stop observing given callback
26myObject.addObserver("event_name", callback);
27
28// register event (should be used within myobject)
29myObject.notify("event_name", "and", "params");
30
31// contains callbacks by events
32myObject.observers
33
34// remove observable
35withObservable.dispose.call(myObject);
36

Recommendations

Within a Constructor use the mixin as follows

AClass.UPDATE_EVENT = "update";
AClass.END_EVENT = "end";

function AClass() {
    withObservable.call(this, [AClass.UPDATE_EVENT, AClass.END_EVENT]);
}

This ensures that

• The event names are accessible from outside
• refactoring of eventnames is simple
• better overview of actual events
• calling withObservable in constructor prevents conflicts