Stoyan (@stoyanstefanov) is a Facebook engineer, former Yahoo!, writer ("JavaScript Patterns", "React: Up and Running"), speaker (JSConf, Velocity, Fronteers), toolmaker (Smush.it, YSlow 2.0) and a guitar hero wannabe. Let’s talk a bit about keeping tabs on how much CPU is consumed by an application’s JavaScript. And let’s frame the discussion around components – the atomic building blocks of the
![JavaScript component-level CPU costs](https://cdn-ak-scissors.b.st-hatena.com/image/square/6451f01ba22b7eb4aed839dd4a4d05908ba2931f/height=288;version=1;width=512/https%3A%2F%2Fcalendar.perfplanet.com%2Fwp-content%2Fuploads%2F2019%2F12%2Fstoyan%2Fchrome-tracing.png)