JSFiddle - React, Tailwind, and code Playground

JavaScript

var url = "http://www.mysite.com?foo=bar&paramNamePrefixXXX=value&fizz=buzz",
    prefix = "paramNamePrefix";

var desiredValue = url.match(new RegExp('[?&]' + prefix + '.*?=(.*?)[&#$]', ''));
desiredValue = desiredValue && desiredValue[1];

console.log(desiredValue); // -> "value"