caching

cache-middleware.js

function (duration) {     
    // cutted code
    return (req, res, next) => {
    // cutted code
    if (res.locals.ratelimited) {
        if (cacheContent) {
             res.setHeader(cacheKeyHeader, 'HIT');
             res.status(200).send(cacheContent);
             return;
         } else {
             res.status(500).send(errorPage);
             return;
         }
    }

    if (!isMember && cacheContent) {
        res.setHeader(cacheKeyHeader, 'HIT');
        res.status(200).send(cacheContent);
        return;
    }

    if (!cacheContent) {
        res.locals.sendResponse = res.send;
        res.setHeader(cacheKeyHeader, 'HIT');
        res.send = (body) => {
            if (res.statusCode === 200) {
                memCache.put(key, body, duration * 1000);
            }
            res.locals.sendResponse(body);
        }
    }
    next();
    }
}