JSFiddle - React, Tailwind, and code Playground

JavaScript

var obj = {
    param1: 'something',
    param2: 'somethingelse',
    param3: 'another'
};

var serialiseObject = function(obj) {
    var pairs = [];
    for (var prop in obj) {
        if (!obj.hasOwnProperty(prop)) {
            continue;
        }
        pairs.push(prop + '=' + obj[prop]);
    }
    return pairs.join('&');
}

document.body.innerHTML = serialiseObject(obj);