Modifying axis labels via scales::number() introduces NAs in combination with facetted_pos_scales()

Question

I have the following butterfly plot that works as expected thanks to the ggh4x package.

librarian::shelf(ggpol, tidyverse)

dat <- 
  tibble(group = rep(letters[1:5], each = 2),
         type = factor(paste0("type", rep(c(1:2), 5))),
         value = c(-50, 110, -45, 120, -40, 130, -35, 140, -30, 150))

dat %>% 
  ggplot(aes(x = value, y = group)) +
  geom_col() +
  facet_share(~type, scales = "free", reverse_num = TRUE) +
  facetted_pos_scales(
    x = list(scale_x_continuous(limits = c(-40, -30)),
             scale_x_continuous(limits = c(35, 215))))

When I try to modify the left x axis labels via labels = scales::label_number(decimal.mark = ",") NAs are introduced.

dat %>% 
  ggplot(aes(x = value, y = group)) +
  geom_col() +
  facet_share(~type, scales = "free", reverse_num = TRUE) +
  facetted_pos_scales(
    x = list(scale_x_continuous(limits = c(-40, -30),
                                labels = label_number(decimal.mark = ",")),
             scale_x_continuous(limits = c(35, 215))))

When I try the same for the right axis, the problem does not appear. (I use label_percent() because there are no decimal points in the right axis to change. But similarly label_percent() would not work on the left axis.

dat %>% 
  ggplot(aes(x = value, y = group)) +
  geom_col() +
  facet_share(~type, scales = "free", reverse_num = TRUE) +
  facetted_pos_scales(
    x = list(scale_x_continuous(limits = c(-40, -30)),
             scale_x_continuous(limits = c(35, 215),
                                labels = label_percent())))

What is the problem here and how can I solve it?

Answer 1

The issue is not related to ggh4x::facetted_pos_scales but due to setting reverse_num=TRUE which according to the docs

will multiply the axis labels for that panel by -1.

Haven't had a closer look but would guess that this multiplication is done on the formatted labels and hence will result in the NAs.

To fix that set reverse_num=FALSE and transform the mnumerics before applying the scales::label_number, e.g. by using abs():

library(tidyverse)
library(ggpol)
library(ggh4x)

dat <-
  tibble(
    group = rep(letters[1:5], each = 2),
    type = factor(paste0("type", rep(c(1:2), 5))),
    value = c(-50, 110, -45, 120, -40, 130, -35, 140, -30, 150)
  )

dat %>%
  ggplot(aes(x = value, y = group)) +
  geom_col() +
  facet_share(~type, scales = "free") +
  facetted_pos_scales(
    x = list(
      scale_x_continuous(
        limits = c(-40, -30),
        labels = ~scales::label_number(decimal.mark = ",")(abs(.x))
      ),
      scale_x_continuous(limits = c(35, 215))
    )
  ) +
  theme(axis.text.x = element_text(size = 20))