library(leaflet)
leaflet() %>%
addProviderTiles("CartoDB.Positron") %>%
addCopyExtent(event.code = "KeyE") %>%
addMouseCoordinates()
# now click on the map (!) and zoom to anywhere in the map, then press 'e' on
# your keyboard. This will copy the current extent/bounding box as a JSON object
# to your clipboard which can then be parsed with:
# jsonlite::fromJSON()
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