JSFiddle - React, Tailwind, and code Playground

JavaScript

var hash = 'one=1&two=2+3+4',
    split = hash.split('&');

var obj = {};
for(var i = 0; i < split.length; i++){
    var kv = split[i].split('=');
    obj[kv[0]] = decodeURIComponent(kv[1] ? kv[1].replace(/\+/g, ' ') : kv[1]);
}
console.log(obj);