as_mapper()

library(purrr)
mult <- as_mapper(~ .x * 2)
map(list(airquality, mtcars), 
    mult)

[[1]]
    Ozone Solar.R Wind Temp Month Day
1      82     380 14.8  134    10   2
2      72     236 16.0  144    10   4
3      24     298 25.2  148    10   6
4      36     626 23.0  124    10   8
5      NA      NA 28.6  112    10  10
6      56      NA 29.8  132    10  12
...