9. Bundle analyzing#

Once you start developing your custom Volto project, you'll load a lot of third party code, your own code, etc. In short, you'll be asking your visitors to load, parse and execute a lot of JavaScript code.

One of the key techniques to avoid loading all Volto code at once is to use the Webpack code splitting feature, which allows the big JavaScript files to be split and load "on demand", as soon as new components require it. See more about this in the Lazy Loading chapter.

To understand how much of an impact, and how to further optimize the chunking process, Volto includes integration with the Webpack Bundle Analyzer. To trigger it, run:

yarn analyze

This will trigger a production build (yarn build) and then open a browser at http://localhost:8888 where you can see the way your JS static resources bundle has been split into chunks and the content of each chunk.