Seeing inside the bundle
Bundle analysis inspects the built output to show what each module contributes to total size. Without it, a bundle is a black box and you cannot tell which dependency made it heavy.
- Analyzers visualize chunks and modules, often as a treemap by size.
- You see which packages and files dominate the bytes.
- Surprises like a huge date library or duplicate copies become visible.
Acting on findings
Once you can see the weight, you can target the worst offenders.
- Replace a large dependency with a smaller or built in alternative.
- Remove duplicate versions of the same library from different paths.
- Lazy load heavy features so they leave the initial chunk.
Analysis pairs naturally with tree shaking and code splitting, it tells you where those techniques will pay off most. Measure both raw and compressed sizes, since gzip changes the ranking. The point is to make size driven decisions from evidence rather than guesses, then confirm the bundle shrank after each change.
Key idea
Bundle analysis visualizes what each module adds to total size so you can target bloat, remove duplicates, and lazy load heavy code, turning size decisions into evidence based changes instead of guesses.