RxJS to$q for angular 1.2.XXX

rx.observable.to$q.js

rx.Observable.prototype.to$q = function(onFulfiled, onRejected) {
    var source = this;
    var deferred = $q.defer();

    var value, hasValue = true;
    source.subscribe(function(v) {
        value = v;
        hasValue = true;
    }, deferred.reject, function () {
        hasValue && deferred.resolve(value);
    });
    return deferred.promise.then(onFulfiled, onRejected);
};

When using angular 1.2.xxx, you are stuck with the deferred based $q.