Using decoders in monorepos

In a monorepo, you might have a shared package that defines decoders (e.g. your validation schemas), used by multiple apps. If the shared package lists decoders as a regular dependency, each package can resolve its own copy. This means multiple copies of decoders can end up in your bundle, increasing bundle size. Worse, when those copies are different versions, things can break at runtime, because decoder instances from one copy aren't recognized by another.

The fix: declare decoders as a peer dependency in the shared package. This tells the package manager to use the host app's copy instead of installing a separate one.

In your shared package's package.json:

{
  "peerDependencies": {
    "decoders": "*"
  }
}

The peerDependencies entry tells consumers to provide whichever version of decoders they want to use, and the shared package will adjust to that. Using "*" as the version range is typically the road of least pain.

Checking for duplicates

If you suspect multiple copies of decoders are being bundled, check with:

npm ls decoders

This shows the dependency tree. If you see decoders listed more than once at different versions, you likely have the duplication problem described above. Switching to a peer dependency in the inner package will fix it.