Datetime scales don't support out of bounds (oob) arguments #4199

I've noticed that date/time scales do not support the oob argument that the continuous scales have, while I do think this might be a useful feature.

Let's say I have the following graph, of which I would want the x-axis labelling:

library(ggplot2)

ggplot(economics, aes(date, unemploy)) +
  geom_line() +
  scale_x_date(limits = as.Date(c("1970-01-01", "2010-01-01")))
#> Warning: Removed 93 row(s) containing missing values (geom_path).

But I'd like the line to look like the following:

ggplot(economics, aes(as.numeric(date), unemploy)) +
  geom_line() +
  scale_x_continuous(
    limits = as.numeric(as.Date(c("1970-01-01", "2010-01-01"))),
    oob = scales::oob_squish
  )

^{Created on 2020-09-11 by the reprex package (v0.3.0)}

This does not currently seem possible. However, as the ggplot2:::datetime_scale() function passes the ... to continuous_scale() (which does use oob), it would seem most of the infrastructure for oob arguments is already there.

Thanks for considering!