# detect-monorepo

> Detect whether a directory sits inside a JS/TS monorepo workspace (pnpm, npm/yarn/bun workspaces, or rush).

Latest version **1.2.0** (published 2026-05-08) · MIT license · 0 weekly downloads

## Install

```sh
npm install detect-monorepo
pnpm add detect-monorepo
yarn add detect-monorepo
bun add detect-monorepo
```

## Health

**Score 65/100 (B)** — status: active.

Positive: has types; esm support; no vulnerabilities; has provenance; high quality score.

Warnings: low downloads.

## Facts

| | |
|---|---|
| Version | 1.2.0 |
| Published | 2026-05-08 |
| First published | 2026-04-10 |
| Weekly downloads | 0 |
| License | MIT |
| TypeScript types | bundled |
| Module format | ESM + CommonJS |
| Node | >=20.0.0 |
| Dependencies | 0 |
| Unpacked size | 28.9 KB |
| Known vulnerabilities | 0 |
| Install scripts | no |
| Provenance | attested (GitHub Actions) |
| GitHub stars | 0 |
| Author | Thijs Koerselman |
| Maintainers | thijskoerselman |
| Keywords | bun, detect, monorepo, npm, pnpm, rush, workspace, workspaces, yarn |

## Links

- npm: https://www.npmjs.com/package/detect-monorepo
- Repository: https://github.com/0x80/detect-monorepo
- Homepage: https://github.com/0x80/detect-monorepo#readme
- Issues: https://github.com/0x80/detect-monorepo/issues
- npm.io page: https://npm.io/package/detect-monorepo

## Alternatives

- [raw-loader](https://npm.io/package/raw-loader.md) — 4.3M weekly downloads
- [plop](https://npm.io/package/plop.md) — 1.4M weekly downloads
- [webpack-deadcode-plugin](https://npm.io/package/webpack-deadcode-plugin.md) — 80.3K weekly downloads
- [@storybook/preact-vite](https://npm.io/package/@storybook/preact-vite.md) — 54.2K weekly downloads
- [vite-plugin-transform](https://npm.io/package/vite-plugin-transform.md) — 2.4K weekly downloads

## Recent versions

- 1.2.0 (latest) — 2026-05-08
- 1.1.0 — 2026-04-10
- 1.0.0 — 2026-04-10

## README

# detect-monorepo

A tiny, zero-dependency helper that walks upward from a starting directory to
decide whether it sits inside a JS/TS monorepo workspace.

It recognises:

- pnpm workspaces (`pnpm-workspace.yaml`)
- npm, yarn, and bun workspaces (`workspaces` field in `package.json`)
- Rush (`rush.json`)

It is intended for tools that need a cheap pre-check before loading heavier
monorepo tooling — for example,
[`isolate-package`](https://github.com/0x80/isolate-package) is only useful
inside a monorepo, so consumers like
[`firebase-tools-with-isolate`](https://github.com/0x80/firebase-tools-with-isolate)
can call `detectMonorepo` first and only pay the cost of loading
`isolate-package` when a workspace is actually detected.

## Install

```sh
pnpm add detect-monorepo
# or
npm install detect-monorepo
```

## Usage

```ts
import { detectMonorepo } from "detect-monorepo";

const info = detectMonorepo();
// or pass an explicit start directory:
const info = detectMonorepo("/path/to/some/package");

if (info) {
  console.log(`Monorepo detected at ${info.rootDir} (kind: ${info.kind})`);
} else {
  console.log("Not inside a monorepo");
}
```

The function returns either `null` or:

```ts
type MonorepoInfo = {
  /** Absolute path to the monorepo workspace root. */
  rootDir: string;
  /** Which workspace marker was found. "workspaces" covers npm/yarn/bun. */
  kind: "pnpm" | "workspaces" | "rush";
};
```

## Behaviour

- Walks upward from `startDir` (default: `process.cwd()`) until a workspace
  marker is found, a directory containing a VCS-root marker (`.git`, `.hg`,
  or `.svn`) is reached, or the filesystem root is reached. The
  VCS-bearing directory is itself checked for workspace markers before
  traversal stops, so a workspace root and a repo root may coincide. For
  projects inside a VCS working copy the boundary prevents the walk from
  straying outside the repository into unrelated workspace markers higher
  up the filesystem; outside a VCS working copy there is no such bound and
  the walk continues to the filesystem root.
- Returns the first match found while walking upward.
- A `package.json` that cannot be parsed, or one whose `workspaces` field
  isn't an array or a `{ packages: string[] }` object, is treated as "no
  workspace marker here" — the walk continues upward.
- Requires Node.js 20 or newer.

## License

MIT © Thijs Koerselman

---
_Source: https://npm.io/package/detect-monorepo · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._