Problem

The current custom formatter API does not allow me to import my runtime module with locale awareness.

Current:

export const phone: CustomFormatter = {
  // ...snip
  module: '@messageformat/phone'
};

Desired:

export const phone: CustomFormatter = {
  // ...snip
  module: (localeCode) => `@messageformat/phone/${localeCode}` // e.g. "@messageformat/phone/mx"
};

Discussion

In this respect, the generated ESM javascript can use much smaller implementations for the compilation of interest!