On a technical side, ubiquity of javascript ensures that performance of common cases will be looked at and improved, if not yet. But as a fellow former low-lev

On a technical side, ubiquity of javascript ensures that performance of common cases will be looked at and improved, if not yet. But as a fellow former low-level, my humble advice is: stop worrying and write clear code. Clear code eventually will run fast and stay clear. Nuanced code eventually will run as fast but stay nuanced.