That function is s simple wrapper around reshape and lattice.
A simple approximation would be:
library(tidyverse)
# Species is the outcome for classification
iris %>%
gather(predictor, value, -Species) %>%
ggplot() +
aes(x = Species, y = value) +
geom_boxplot() +
facet_wrap(~ predictor, scales = "free_y")
# regression example:
mtcars %>%
gather(predictor, value, -mpg) %>%
ggplot() +
aes(x = value, y = mpg) +
geom_point() +
facet_wrap(~ predictor, scales = "free_x")