How to capture query string parameters from network tab programmatically

I am trying to capture query string parameters for analytics purpose using javascript. I did some searching and found that BMP can be used to do it but i am unable to find ample examples to implement. Could anyone point me in the right direction.

EDIT 1: I used below code using browsermob-proxy to get har file but i get ERROR: browsermob-proxy returned error when i run it . I use selenium with it.

getHarFile() {
        const proxy = browsermb.Proxy;
        const pr = new proxy({host:"0.0.0.0",port:4444});
        pr.doHAR("http://www.cnn.com/", (err,data) => {
            if (err) {
                logger.debug('ERROR: ' + err);
            } else {
                fs.writeFileSync('ua.com.har', data, 'utf8');
                logger.debug("#HAR CREATED#");
            }
        })
    }