const fontSizeArr = ['8px', '9px', '10px', '12px', '14px', '16px', '20px', '24px', '32px', '42px', '54px', '68px', '84px', '98px'];

const Size = ReactQuill.Quill.import('attributors/style/size');
Size.whitelist = fontSizeArr;
ReactQuill.Quill.register(Size, true);

I am trying to have customize fontsize with QuillJs but it's not working. The error says Document is not defined.