Helper for creating a pie chart
Arguments
- bb
- A - billboard- htmlwidgetobject.
- data
- A - data.frame, first column should contain labels, second column values associated, except if mapping is provided.
- mapping
- Mapping of variables on the chart, see - bbaes.
- ...
- Arguments for slot pie, https://naver.github.io/billboard.js/release/latest/doc/Options.html#.pie. 
Note
This function can be used with billboarderProxy in shiny application.
Examples
stars <- data.frame(
  package = c("billboarder", "ggiraph", "officer", "shinyWidgets", "visNetwork"),
  stars = c(9, 177, 43, 44, 169)
)
# Default
billboarder() %>% 
  bb_piechart(data = stars)
# Explicit mapping
billboarder() %>% 
  bb_piechart(data = stars, bbaes(package, stars))
# Other way to specify mapping
billboarder(data = stars) %>% 
  bb_aes(package, stars) %>% 
  bb_piechart()