# egoist/tsup · RepoSense Release & Migration Intelligence

> Migrate to obug, drop node < 22.18 - by @sxzz (59bfd). Review breaking API changes before upgr… Migration: Moderate.

## Metadata
- **Repository URL**: https://github.com/egoist/tsup
- **Primary Package**: `tsup` (NPM)
- **Categories**: `BUILD_TOOL`
- **Latest Version**: `v9.0.0`
- **Semantic Status**: `BREAKING`
- **Bundle Size Impact (unavailable)**: `Size Unavailable`
- **Atom Ingestion Feed**: https://github.com/egoist/tsup/releases.atom

## The Human Context (Plain-English Pitch)
tsup is an open-source library and developer tool in the egoist/tsup ecosystem. It saves developers from writing repetitive low-level boilerplate from scratch by providing a battle-tested, open-source implementation ready for production.

## Stage 1 Executive Summary ([Core Change] + [Required Action] + [Migration Effort])
Migrate to obug, drop node < 22.18 - by @sxzz (59bfd). Review breaking API changes before upgr… Migration: Moderate.

## Breaking Changes & Required Actions
- [BREAKING] Migrate to obug, drop node < 22.18 - by @sxzz (59bfd)
- [BREAKING] Remove `baseUrl` in tsconfig - by @pxseu in #1390 (98052)
- Migrate to obug, drop node < 22.18 - by @sxzz (59bfd)
- Upgrade esbuild & chokidar - by @sxzz (a2c08)
- **type**: Expose the Plugin type - by @Sunny-117 in #1264 (3079e)
- Remove `baseUrl` in tsconfig - by @pxseu in #1390 (98052)

## Migration Snippet
```ts
npm install tsup@9.0.0
```

## Ecosystem Compatibility Matrix & Graph Warnings
- **TypeScript 5.x** [`COMPATIBLE`]: Ships standard TypeScript declaration files without type regressions.

## Zero-Noise Release Timeline
- **v9.0.0** (2026-10-14) [BREAKING]: Migrate to obug, drop node < 22.18 - by @sxzz (59bfd). Review breaking API changes before upgr… Migration: Moderate.

## Upgrade & Migration Q&A (GEO Direct Answers)
### Is egoist/tsup v9.0.0 safe to upgrade in production?
egoist/tsup v9.0.0 is classified as BREAKING (MAJOR release). Migrate to obug, drop node < 22.18 - by @sxzz (59bfd). Review breaking API changes before upgr… Migration: Moderate.

### What breaking changes or compatibility risks exist in egoist/tsup v9.0.0?
Migrate to obug, drop node < 22.18 - by @sxzz (59bfd) Remove `baseUrl` in tsconfig - by @pxseu in #1390 (98052)

### What is the bundle size impact of tsup v9.0.0?
Measured bundle size telemetry is currently unavailable for tsup v9.0.0; verify build output locally before deploying.

### How do I upgrade tsup to v9.0.0?
Upgrade tsup to v9.0.0 by running "npm install tsup@9.0.0" and applying the migration steps: npm install tsup@9.0.0