Prosemirror-Model: Add missing optional target argument to serializeFragment function

[mmackeyatl]

Adding missing optional "target" argument type to serializeFragment function as per issue raised in DefinitelyTyped repo (@types-prosemirror-model):
DefinitelyTyped/DefinitelyTyped#57668

[marijnh]

That's intentionally private. Did you need it in a real-world use case?

[mmackeyatl]

We're trying to write a custom serializer for clipboardSerializer to add some logic. For this we also needed to manually call serializeFragment ourselves as we want to preserve the original serializer's logic too.

customSerializer.serializeFragment = (content, options, target) => {
  if (thing) {
    let newContent;
    return originalSerializeFragment(newContent, options, target);
  }
  return originalSerializeFragment(content, options, target);
};

[marijnh]

Subclassing stuff is not generally supported in this library. It seems like this use case could also be handled by a pre-processing pass on the content, no?

[mmackeyatl]

How/where could we do the pre-processing pass on the content when we need to transform what's being written to the clipboard?

[marijnh]

That's a good point. I've updated the docs in attached patch to clarify that only the serializeFragment method of clipboardSerializer will be called, and you may provide an alternative object that provides that method. Does that help?