na.md
In forcats: Tools for Working with Categorical Variables (Factors)

checks input types

Code
  fct_na_value_to_level(1)
Condition
  Error in `fct_na_value_to_level()`:
  ! `f` must be a factor or character vector, not a number.
Code
  fct_na_value_to_level(f, level = 1)
Condition
  Error in `fct_na_value_to_level()`:
  ! `level` must be a single string or `NA`, not the number 1.
Code
  fct_na_level_to_value(1)
Condition
  Error in `fct_na_level_to_value()`:
  ! `f` must be a factor or character vector, not a number.
Code
  fct_na_level_to_value(f, extra_levels = 1)
Condition
  Error in `fct_na_level_to_value()`:
  ! `extra_levels` must be a character vector or `NULL`, not the number 1.