src/preferences/PreferencesBase.js
function (event, preferenceID, handler) {
            if (typeof preferenceID === "function") {
                handler = preferenceID;
                preferenceID = null;
            }

            if (preferenceID) {
                var pref = this.getPreference(preferenceID);
                pref.on(event, handler);
            } else {
                this._installListener();
                this._on_internal(event, handler);
            }
        }
function (event, preferenceID, handler) {
            if (typeof preferenceID === "function") {
                handler = preferenceID;
                preferenceID = null;
            }

            if (preferenceID) {
                var pref = this.getPreference(preferenceID);
                pref.on(event, handler);
            } else {
                this._installListener();
                this._on_internal(event, handler);
            }
        }
function ( event , preferenceID , handler ) { if ( typeof preferenceID === "function" ) { handler = preferenceID ; preferenceID = null ; } if ( preferenceID ) { var pref = this . getPreference ( preferenceID ) ; pref . on ( event , handler ) ; } else { this . _installListener ( ) ; this . _on_internal ( event , handler ) ; } }
Sets up a listener for events for this PrefixedPreferencesSystem. Only prefixed events
will notify. Optionally, you can set up a listener for a specific preference.

@param {string} event Name of the event to listen for
@param {string|Function} preferenceID Name of a specific preference or the handler function
@param {?Function} handler Handler for the event
Sets up a listener for events for this PrefixedPreferencesSystem . Only prefixed events will notify . Optionally you can set up a listener for a specific preference .