Report invalid module field in package.json

[remcohaszing]

Some packages define the top-level module field in package.json. Although it’s non-standard, bundlers use it. This can lead to differences between usage in the browser and Node.js, but it is not possible to add type definitions for it.

I think it would be useful to report the module field if it does not match the import condition in the package.json exports field nor the main field.

For example:

• monaco-editor
• vscode-json-languageservice
• vscode-uri
• whatwg-fetch

[hfhchan-plb]

openpgp also has the module field, but no corresponding exports field, so ESM only works with bundlers and not node/ts.

[andrewbranch]

Another interesting case: qr-creator, where main is a browser script, module is a .js file that contains ESM syntax, and types is a .d.ts file that represents module 😵‍💫