JSFiddle - React, Tailwind, and code Playground
JavaScript
var json = ('{"data":{"username":"Brad","userID":941022167561310208,"location":"London","test":"3908349804","test2":"This already exists in 034093049034 quotes"},"list":[3409823408,3409823408,"A list 234908234"]}').replace(/([\[:])?(\d+)([,\}\]])/g, "$1\"$2\"$3");
json = JSON.parse(json);
$('body').append("<pre>" + JSON.stringify(json, undefined, 4) + "</pre>");