addCustomTime: Add a new vertical bar at a time point that can be dragged by...
In westdana/Timeline: Create Interactive Timeline Visualizations in R

Add a new vertical bar at a time point that can be dragged by the user

1	addCustomTime(id, time, itemId)

`id`	Timeline id or a `timevis` object (the output from `timevis()`)
`time`	The date/time to add
`itemId`	The id of the custom time bar

timevis() %>%
  addCustomTime(Sys.Date() - 1, "yesterday")

if (interactive()) {
library(shiny)
shinyApp(
  ui = fluidPage(
    timevisOutput("timeline"),
    actionButton("btn", "Add time bar 24 hours ago")
  ),
  server = function(input, output) {
    output$timeline <- renderTimevis(
      timevis()
    )
    observeEvent(input$btn, {
      addCustomTime("timeline", Sys.Date() - 1, "yesterday")
    })
  }
)
}