The cost of JavaScript

Carlos Morales • 2019-07-01

Last year I read the Cost of JavaScript in 2018 by Addy Osmani (V8 engine team), my two learning lessons were:

• short time to first interaction is the most important performance metric,
• parsing JS code is quite expensive, not just downloading and executing, this meant polyfill files need to be added carefully.

This year The Cost of JavaScript in 2019 emphasizes in smaller JS bundlers and takes a deeper look into parsing/compiling costs.

I applied these lessons when designing the new frontend architecture at my current company. Performance has become a very important user experience factor. Having a shorter time to first interaction (when the page becomes interactive) has become the goal to focus for the whole industry.

Both articles are great, specially if you want to understand the performance bottlenecks at the browser. I could not explain it better. Just read them. :smiley: