For workerDirectory when using msw in workspace used within a certain npm workspaces.

[k35o]

Suppose npm workspaces is constructed as follows.

- root(package.json)
  - workspaceA(package.json)
  - workspaceB(package.json)

And assume that msw is used only within workspaceA.

// workspaceA/package.json
{
  ...,
  "devDependencies": {
    ...,
    "msw": "2.0.0",
    ...,
  },
  ...,
  "msw": {
    "workerDirectory": "./public"
  }
}

Running npm i -D msw@latest -w workspaceA in this situation will not update mockServiceWorker.js to see package.json in the root directory.

msw/config/scripts/postinstall.js

Line 8 in b3e47f7

const parentPackageCwd = process.env.INIT_CWD

How can I configure workspaceA/package.json for updating mockServiceWorker.js?
I don't want to write msw.workerDirectory in the root package.json, Because I don't want to leak workspaceA information out.

[kettanaito]

Hi, @k35o.

The msw.workerDirectory must always be specified in the root-level package.json. That's the CWD you have when you run npm install. MSW cannot and mustn't assume workspaces or -w flags.

Here's what you should do instead.

1. npm i msw@latest -D -w packageA
2. npx msw init ./packages/packageA --save (from the root).

This will store the public path of your nested package for future MSW updates in the root-level package.json:

// ./package.json
{
  "msw": {
    "workerDirectory": ["./packages/packageA/public"]
  }
}

You can also keep a list of values in case multiple packages in your monorepo need the worker script.

Related materials

• Managing the worker