Selecting a consecutive entity range in draft-js

gistfile1.js

const maybeSelectConsecutiveEntity = editorState => {
  const selection = editorState.getSelection();

  if (!selection.isCollapsed()) {
    return editorState;
  }

  const startKey = selection.getStartKey();
  const startOffset = selection.getStartOffset();
  const prevOffset = startOffset - 1;
  const block = editorState.getCurrentContent().getBlockForKey(startKey);
  const characterList = block.getCharacterList();
  const prevChar = characterList.get(prevOffset);
  const nextChar = characterList.get(startOffset);

  if (!prevChar || !nextChar) {
    return editorState;
  }

  const prevEntity = prevChar.getEntity();
  const nextEntity = nextChar.getEntity();
  const entity = prevEntity === nextEntity && prevEntity;

  if (!entity) {
    return editorState;
  }

  let finalPrevOffset = prevOffset;
  let finalNextOffset = startOffset;

  while(finalPrevOffset > 0) {
    finalPrevOffset--;
    const char = characterList.get(finalPrevOffset);
    if (char.getEntity() !== entity) {
      finalPrevOffset++;
      break;
    }
  }

  const blockLength = block.getLength();
  while(finalNextOffset < blockLength) {
    finalNextOffset++;
    const char = characterList.get(finalNextOffset);
    if (char.getEntity() !== entity) {
      break;
    }
  }

  return EditorState.forceSelection(editorState, selection.merge({
    anchorOffset: finalPrevOffset,
    focusOffset: finalNextOffset,
  }));
}