https://github.com/ramnathv/htmlwidgets
127 charts
http://gallery.htmlwidgets.org/
chapter 14
https://www.crumplab.com/psyc7709_2019/book/docs/creating-your-own-html-widget.html
chapter 3
https://book.javascript-for-r.com/widgets-intro-intro.html
chapter 4.4
https://bookdown.org/rdpeng/RProgDA/htmlwidgets.html
https://dreamrs.github.io/apexcharter/index.html
https://mpn.metworx.com/packages/htmlwidgets/1.5.4/articles/develop_intro.html