Core: Trigger watchForError callbacks from setError

[fernanDOTdo]

Design: Trigger watchForError callbacks from setError

Problem

ENGrid.watchForError() observes .en__errorList for added children, but ENGrid.setError() adds .en__field__error directly to a field wrapper. As a result, callbacks registered through watchForError do not run when setError displays a field-level error.

Goal

Make setError trigger all callbacks registered with watchForError, without breaking backward compatibility.

Constraints

• Keep existing public signatures: setError(element, errorMessage) and watchForError(callback).
• Preserve the deduplication behavior already in watchForError (callback key derived from callback.toString()).
• The only current consumers are ENGrid.enableSubmit and iFrame.sendIframeHeight; both are idempotent.

Approach: Shared Callback Registry

Add a module-level Map<string, Function> to packages/scripts/src/engrid.ts. watchForError registers the callback in the map and also attaches the existing .en__errorList MutationObserver. setError iterates the map and invokes each registered callback after injecting the field-level error.

Changes

• packages/scripts/src/engrid.ts
  • Add const errorCallbacks = new Map<string, Function>(); at module scope.
  • Refactor the callbackType derivation into a private helper so both watchForError and setError can use it.
  • In watchForError, register the callback in the map before attaching the observer.
  • In setError, after adding/updating .en__field__error, invoke every callback in the map.

Backward Compatibility

• Signatures unchanged.
• Callbacks now fire for field-level errors created by setError. This is the intended behavior change.
• Existing deduplication keying is preserved.