Angular message bus and smartWatch

rootScopeExtensionsModule.js

angular.module('rootScopeExtensionsModule', [])

.config($provide => {
    $provide.decorator('$rootScope', $delegate => {
        var rootScope = $delegate;

        Object.defineProperty(rootScope.constructor.prototype, '$bus', {
            get: function() {
                return {
                    publish: (msg, data) => {
                        // emit goes to parents, broadcast goes down to children
                        // since rootScope has no parents, this is the least noisy approach
                        // however, with the caveat mentioned below
                        rootScope.$emit(msg, data);
                    },
                    subscribe: (msg, func) => {
                        // ignore the event.  Just want the data
                        var unbind = rootScope.$on(msg, (event, data) => func(data));
                        // being able to enforce unbinding here is why decorating rootscope
                        // is preferred over DI of an explicit bus service
                        this.$on('$destroy', unbind);
                    }
                };
            }
        });

        Object.defineProperty(rootScope.constructor.prototype, '$smartWatch', {
            get: function() {
                return (expression, handler) => {
                    return this.$watch(expression, (newValue, oldValue) => {
                        if (oldValue !== newValue)
                            handler();
                    }, true);
                };
            }
        });

        return rootScope;
    });
});