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

 
// mixin the observable behaviour:
// myobject.observers;
// myobject.addObserver;
// myobject.addObserverOnce;
// myobject.removeObserver;
// myobject.notify;
myObject = withObservable.call(myObject, ["event_name", "another_event"]);
 
// register to an event
myObject.addObserver("event_name", function () {
    // do something
});
 
// register to an event once
myObject.addObserver("event_name", function () {
    // do something, will never be called again
});
 
// prioritize an event listener (gets executed first)
myObject.addObserver("event_name", function () {
    // do something
}, true);
 
// stop observing given callback
myObject.addObserver("event_name", callback);
 
// register event (should be used within myobject)
myObject.notify("event_name", "and", "params");
 
// contains callbacks by events
myObject.observers
 
// remove observable
withObservable.dispose.call(myObject);
 

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