Performant, conformant JSON parser avoids loss of precision in JavaScript

I made this to work with Zapatos, which uses Postgres JSON extensively.<p>Note that there is a proposal to make this possible with native JSON.parse and JSON.stringify, which would be awesome: <a href="https:&#x2F;&#x2F;github.com&#x2F;tc39&#x2F;proposal-json-parse-with-source">https:&#x2F;&#x2F;github.com&#x2F;tc39&#x2F;proposal-json-parse-with-source</a>