What problem did you solve?

Closes #776

Since JSON does not support NA, NaN, Inf values, they can only be written as strings in the following way:

jsonlite::write_json(x, file, na = "string", null = "null", auto_unbox = TRUE)

One remaining issue is that these values will not work properly when filtering is used in the data viewer, i.e. if one filters a column by "Greater than 0", Inf is not regarded as Inf > 0 but ignored.

(If you have)Screenshot

How can I check this pull request?

The following code should open a data viewer where Inf and NA values are correctly displayed in the data grid.

dt <- data.frame(
  id = 1:6,
  x = c(1, 2, NA, 3, Inf, -Inf),
  y = c("A", "B", NA, NA, NA, "D")
)

View(dt)