Revert #167

As it breaks ggforce and doesn't fix the motivating problem described in #166.

NEWS.md

@@ -116,9 +116,6 @@
 
 * `date_breaks()` now supports subsecond intervals (@dpseidel, #85).
 
-* `train_continuous()` now maintains the class of inputs when they are not
-  numeric (@billdenney, #166).
-
 # scales 1.0.0
 
 ## New Features

R/scale-continuous.r

@@ -30,6 +30,8 @@ cscale <- function(x, palette, na.value = NA_real_, trans = identity_trans()) {
 
 #' Train (update) a continuous scale
 #'
+#' Strips attributes and always returns a numeric vector
+#'
 #' @inheritParams train_discrete
 #' @export
 train_continuous <- function(new, existing = NULL) {
@@ -38,12 +40,8 @@ train_continuous <- function(new, existing = NULL) {
   if (is.factor(new) || !typeof(new) %in% c("integer", "double")) {
     stop("Discrete value supplied to continuous scale", call. = FALSE)
   }
-  # range(NULL, x) strips attributes
-  if (is.null(existing)) {
-    suppressWarnings(range(new, na.rm = TRUE, finite = TRUE))
-  } else {
-    suppressWarnings(range(existing, new, na.rm = TRUE, finite = TRUE))
-  }
+
+  suppressWarnings(range(existing, new, na.rm = TRUE, finite = TRUE))
 }
 
 # Map values for a continuous palette.

tests/testthat/test-scale.r

@@ -26,16 +26,11 @@ test_that("train_continuous stops on discrete values", {
   )
 })
 
-test_that("train_continuous maintains class with `existing=NULL`.", {
-  expect_equal(
-    train_continuous(1:5),
-    c(1, 5)
-  )
-  my_date <- as.POSIXct("2018-01-01")
-  expect_equal(
-    train_continuous(my_date),
-    c(my_date, my_date)
-  )
+test_that("train_continuous strips attributes", {
+  expect_equal(train_continuous(1:5), c(1, 5))
+
+  x <- as.Date("1970-01-01") + c(1, 5)
+  expect_equal(train_continuous(x), c(1, 5))
 })
 
 test_that("train_continuous changes class to the class of `existing` when not NULL.", {