I released 3 open source libraries that are used in Swaranotebook(https://studio-kalavati.github.io).
Sargam-spec (https://github.com/Studio-kalavati/sargam-spec): A JSON friendly specification to share Raga music notations. Swaranotebook uses this format to store compositions.
Bhatkhande notation viewer: A Clojurescript project that can display compositions notated with Sargam-spec
Chaturpandit: Tooling to display Sargam spec in a notation canvas.