library(apexcharter)
data("consumption")

# specify from and to date
apex(consumption, aes(date, value, group = type), "spline") %>% 
  add_shade(from = "2020-01-06", to = "2020-01-20")

# you can add several shadows
apex(consumption, aes(date, value, group = type), "spline") %>% 
  add_shade(from = "2020-01-06", to = "2020-01-20") %>% 
  add_shade(from = "2020-02-04", to = "2020-02-10")

# or use a vector
apex(consumption, aes(date, value, group = type), "spline") %>% 
  add_shade(from = c("2020-01-06", "2020-02-04"), to = c("2020-01-20", "2020-02-10"))


# automatically add shadow on week-ends
apex(consumption, aes(date, value, group = type), "spline") %>% 
  add_shade_weekend()