Optimizations

This document lists a couple of optimizations that can be performed to reduce the disk size of the static assets and improve loading times.

Removing Applications

Provide the --apps CLI argument once or multiple times, or configure LiteBuildConfig/apps to only copy select applications to the output folder: by default, all of the default applications will be copied to the output folder.

Removing Unused Shared Packages

Provide the --no-unused-shared-packages or LiteBuildConfig/no_unused_shared_packages to prevent copying shared packages used only by removed applications. For lightweight apps like repl, this can result in a much smaller on-disk build.

Warning

Some JupyterLab extensions may require shared packages from the full JupyterLab application, and will not load with this setting.

Removing Source Maps

Provide --no-sourcemaps, or configure LiteBuildConfig/no_sourcemaps in a config file to prevent any .map files from being copied to the output folder. This creates a drastically smaller overall build.

Warning

Removing sourcemaps, in addition to making errors harder to debug, will also cause many 404 errors when a user does open the browser console, which can be even more confusing.

For better baseline performance, the core JupyterLite distribution, and some federated extensions, only ship optimized JavaScript code, which is hard to debug. To improve this, source maps, are also provided to provide pointers to the original source code, and while much larger, are only loaded when debugging in browser consoles.