handleResponse.ts

function handleResponse(res: functions.Response, next?: NextFunction) {

    const url = 'https://firebasestorage.googleapis.com/v0/b/polar-32b0f.appspot.com/o/stash%2F12RMNjmX1PLwqN5fRXzh89Yi7tbL24e5VfCNs4Nq.pdf?alt=media&token=0a2708be-ef63-4791-a338-a3c887b73b19';

    const started = Date.now();
    let idx: number = 0;

    https.get(url, (dataResponse) => {

        res.writeHead(dataResponse.statusCode!,
                      dataResponse.statusMessage,
                      dataResponse.headers);

        res.flushHeaders();

        dataResponse.on("data", data => {
            res.write(data);
        });

        dataResponse.on("end", () => {
            res.end();

            if (next) {
                next();
            }

        });

        dataResponse.on("error", (err) => {
            res.end();
            if (next) {
                next();
            }
        });

    });
}