This JavaScript function returns object with key value pairs primarily made for reactjs to get query string but it works with others too.

getQueryString.js

// @author github.com/debendraoli

function getQueryString(querystring) {
     //check & remove "?" and split each query using "&"
    const string = (querystring.substr(0, 1) === "?" ? querystring.substr(1) : querystring).split('&');
    // generate tuple ["query", "string"] by spliting query: query=string
    // return the object as key value pairs using built-in object.fromEntries
    return Object.fromEntries(string.map(string => string.split("=")));
}

//  getQueryString("?sortby=newest&approved=true")

//  {sortby: "newest", approved: "true"}