What does a barrel file cost?

Briefing

Why does importing a single helper from a barrel file sometimes pull in an entire package, and why does tree shaking not save you?

One tidy index.ts, one import, and suddenly the route bundle contains a charting library nobody on that page uses.

Laboratory

Architecture Lab

Level

SYSTEMS

Estimated time

8 minutes

Method

investigation

Variables under observation

barrel filestree shakingside effectsmodule graphbundling