Ask HN: Any Performance Auditing *Firms* for JS Libraries?

Does anyone have experience having their JavaScript code professionally audited for performance impact and application side effects? (I'm not interested in security audits or general subjective code quality)

I've searched around online, made a few calls to security auditors for leads and found nothing.

I know how to generally test and document the effects of the code myself- I'm really looking a stamp of approval from a third party validator.

What are the actual empirical performance impacts of adding third party JS libraries like Google Analytics?

Example Audit: Real user engagement on various websites across various browsers, on various devices in various locations testing for things like network in/out, impact on rendering times, added latency of user actions like clicks (from added event listeners etc).