1 Commits

Author SHA1 Message Date
robobun
aded701d1d feat(build): add --metafile-md CLI option for LLM-friendly bundle analysis (#26441)
## Summary

- Adds `--metafile-md` CLI option to `bun build` that generates a
markdown visualization of the module graph
- Designed to help Claude and other LLMs analyze bundle composition,
identify bloat, and understand dependency chains
- Reuses existing metafile JSON generation code as a post-processing
step

## Features

The generated markdown includes:

1. **Quick Summary** - Module counts, sizes, ESM/CJS breakdown,
output/input ratio
2. **Largest Input Files** - Sorted by size to identify potential bloat
3. **Entry Point Analysis** - Shows bundle size, exports, CSS bundles,
and bundled modules
4. **Dependency Chains** - Most commonly imported modules and reverse
dependencies
5. **Full Module Graph** - Complete import/export info for each module
6. **Raw Data for Searching** - Grep-friendly markers in code blocks:
   - `[MODULE:]`, `[SIZE:]`, `[IMPORT:]`, `[IMPORTED_BY:]`
   - `[ENTRY:]`, `[EXTERNAL:]`, `[NODE_MODULES:]`

## Usage

```bash
# Default filename (meta.md)
bun build entry.js --metafile-md --outdir=dist

# Custom filename
bun build entry.js --metafile-md=analysis.md --outdir=dist

# Both JSON and markdown
bun build entry.js --metafile=meta.json --metafile-md=meta.md --outdir=dist
```

## Example Output

See sample output: https://gist.github.com/example (will add)

## Test plan

- [x] Test default filename (`meta.md`)
- [x] Test custom filename
- [x] Test both `--metafile` and `--metafile-md` together
- [x] Test summary metrics
- [x] Test module format info (ESM/CJS)
- [x] Test external imports
- [x] Test exports list
- [x] Test bundled modules table
- [x] Test CSS bundle reference
- [x] Test import kinds (static, dynamic, require)
- [x] Test commonly imported modules
- [x] Test largest files sorting (bloat analysis)
- [x] Test output/input ratio
- [x] Test grep-friendly raw data section
- [x] Test entry point markers
- [x] Test external import markers
- [x] Test node_modules markers

All 17 new tests pass.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
Co-authored-by: Dylan Conway <dylan.conway567@gmail.com>
2026-01-28 18:01:39 -08:00