How to use the arangojs/lib/async/util/joinPath.joinPath function in arangojs

{ method, url, headers, body, requestInstrumentation }: RequestOptions,
            callback: Errback
        ) {
            // this is the last change we cancel a request
            // we don't cancel running requests because arangodb does not kill queries when the request ist terminated
            // thus, we keep the request open
            // - to get notified if the request completes pretty quickly anyway so we don't need to kill the query
            // - to take up a socket so that no new query is sent on it while the query is not yet killed
            if (requestInstrumentation && requestInstrumentation.isCancelled) {
                return callback(new Error(`Request has been cancelled by caller before it was sent`));
            }

            notifyAboutPhaseEnd(requestInstrumentation, 'queuing');
            let path = baseUrlParts.pathname
                ? url.pathname
                    ? joinPath(baseUrlParts.pathname, url.pathname)
                    : baseUrlParts.pathname
                : url.pathname;
            const search = url.search
                ? baseUrlParts.search
                    ? `${baseUrlParts.search}&${url.search.slice(1)}`
                    : url.search
                : baseUrlParts.search;
            if (search) {
                path += search;
            }
            if (body && !headers['content-length']) {
                headers['content-length'] = String(Buffer.byteLength(body));
            }
            if (!headers['authorization']) {
                headers['authorization'] = `Basic ${btoa(
                    baseUrlParts.auth || 'root:'