Streams are painful

streams.js

function promiseResponse(request) {
    var deferred = Q.defer();
    request.on("error", deferred.reject);
    request.on("response", deferred.resolve);
    return deferred.promise
    // if you must:
    .fin(function () {
        request.removeListener("error", deferred.reject);
        request.removeListener("response", deferred.resolve);
    });
}

function exists(id) {
    return promiseResponse(knoxClient.head(id))
    .then(function (response) {
       return response.statusCode === 200;
    })
}