V8 Show navigation Home Blog Docs JS/Wasm features Published 25 June 2019 · tagged with internals parsing Note: If you prefer watching a presentation over reading articles, then enjoy the video below! If not, skip the video and read on. “The cost of JavaScript” as presented by Addy Osmani at #PerfMatters Conference 2019. One large change to the cost of JavaScript over the last few years has been an improvement in how fast browsers can parse and compile script. In 2019, the dominant costs of processing scripts are now download and CPU execution time. User interaction can be delayed if the browser’s main thread is busy executing JavaScript, so optimizing bottlenecks with script execution time and network can be impactful. # What does this mean for web developers? Parse & compile costs are no longer as slow as we once thought. The three things to focus on for JavaScript bundles are: Impro...