The one readily available on search: <a href="https:&#x2F;&#x2F;github.com&#x2F;petkaantonov&#x2F;bluebird&#x2F;wiki&#x2F;Optimization-killers#2-unsupported-syntax" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;petkaantonov&#x2F;bluebird&#x2F;wiki&#x2F;Optimization-k...</a><p>Otherwise the fact that engines bailout on optimizing ES6 features was kind of common knowledge when engines started to implement them.