There is already an isPinnedComments elsewhere. Also, can you rename it to isPinnedComment?

isPinnedComments function was in emitter.ts and I put it inside emitDetachedComments because it is not used anywhere else.

Yes, I can rename it.

I think it will be better to not pass in the detachedCommentsInfo array into the function and return currentDetachedCommentInfo and then have a function in emitter call emitDetachedCommentsAndUpdateCommentsInfo that calls into this function and do the following logic

if (detachedCommentsInfo) {
   detachedCommentsInfo.push(currentDetachedCommentInfo);
}
else {
  detachedCommentsInfo = [currentDetachedCommentInfo];
}

So that in the case of using the function in declarationEmitter.ts, we will not be doing throw away work.

also please add return type. And return type and parameter type into JSDoc

also please add return type. And return type and parameter type into JSDoc

I'm not sure how to do that becase I see no other @return or @param in utilities.ts. Can you elaborate?