shiny
htmltools
req()
seq()
on.exit()
observe()
isolate
observeEvent
eventReactive
reactiveTimer()
invalidateLater(ms)
git
mermaid(" graph LR A(Rounded)-->B[Rectangular] B-->C{A Rhombus} C-->D[Rectangle One] C-->E[Rectangle Two] ")
mermaid(" graph LR A[A arr_text] --- B>A arrowtext] ")