Support for ignoring node_modules in sibling packages in monorepo

[IlyaSemenov]

Consider a pnpm monorepo:

packages/foo (depends on axios, bar)
packages/bar (depends on express)

I would like to have foo and bar compiled, but keep axios and express as external.

If I create the build script for foo:

const { build } = require('esbuild')
const { nodeExternalsPlugin } = require('esbuild-node-externals')

build({
  // ...
  plugins: [
    nodeExternalsPlugin({
      allowList: ['bar']
    })
  ]
})

then foo, bar and express are compiled, and only axios is considered external.

Ideally, I would like the plugin to handle the monorepo setup automatically (recognize that bar is not even a package inside node_modules without having to specify any option, not even allowList).

[IlyaSemenov]

To clarify: a sibling monorepo package is referred like this in package.json:

{
  "name": "foo",
  "dependencies": {
    "bar": "workspace:*"
  }
}

I suppose this should be enough to recognize it?

[pradel]

Could be a good way to detect this 👍 Happy to accept a pr for this :)

[marbemac]

Something like the below in utils.ts (perhaps exposed as an option rather than always running) would probably do the trick:

return packageJsonKeys
  .map((key) => {
    if (!packageJson[key]) return [];

    // filter out yarn workspace references
    return Object.keys(packageJson[key]).filter((packageName) => !packageJson[key][packageName].startsWith('workspace:'))
  })
  .flat(1)
  .filter((packageName) => !options.allowList.includes(packageName));

[pradel]

Added in 1.10.0