I built vim-sequence-diagram a few years ago, it's convenient for vimers, but some of my friends complain they don't use vim and I've been experiencing Emacs recently.
I need an editor independent tool to view the JS Sequence Diagram. Here it is.
npm install -g js-seq-viewer
jsv -f {sequence file path}
It launches a web service and opens the view in the default browser when you are editing the sequence file, it reflects the change instantly when you save your file.
MIT