Switch from timetk to slider for sliding window

`timetk` got archived from CRAN at one point, causing this package to get archived as well.

While `timetk` is back up, we only use it for a single function, and that function is basically a re-export from the lower-level `slider` package.

So this removes our dependency on `timetk` and replaces it with a dependency on `slider` instead.

As it turns out, this also gives us better results, since we're able to more clearly note that we're looking for a sliding window on the "time" column of 30 seconds. So the test is updated, and the results look more correct.

Resolves #2

DESCRIPTION

@@ -25,9 +25,9 @@ Imports:
     magrittr (>= 2.0.0),
     rlang (>= 0.4.0),
     tibble (>= 3.0.0),
-    timetk (>= 2.6.0),
+    slider (>= 0.3.0),
     xml2 (>= 1.3.2)
-RoxygenNote: 7.1.1
+RoxygenNote: 7.2.3
 Suggests: 
     covr (>= 3.5.0),
     lintr (>= 3.0.0),

NAMESPACE

@@ -38,11 +38,11 @@ importFrom(lubridate,ymd_hms)
 importFrom(magrittr,"%>%")
 importFrom(rlang,.data)
 importFrom(rlang,abort)
+importFrom(slider,slide_index_dbl)
 importFrom(tibble,add_column)
 importFrom(tibble,is_tibble)
 importFrom(tibble,tibble)
 importFrom(tibble,tribble)
-importFrom(timetk,slidify)
 importFrom(utils,head)
 importFrom(xml2,read_xml)
 importFrom(xml2,xml_add_child)

NEWS.md

@@ -1,5 +1,7 @@
 # activatr (development version)
 
+* Switch dependency from `timetk` to `slider` to avoid unnecessary indirection (#3).
+
 # activatr 0.1.0
 
 * Initial release.

R/act_tbl.R

@@ -80,8 +80,8 @@ is_act_tbl <- function(act_tbl) {
 #' @return \code{summary.act_tbl} returns a tibble with a single row,
 #'         containing a summary of the given \code{act_tbl}.
 #' @importFrom dplyr lag mutate pull slice
-#' @importFrom lubridate as.duration
-#' @importFrom timetk slidify
+#' @importFrom lubridate as.duration dseconds
+#' @importFrom slider slide_index_dbl
 #' @importFrom tibble tribble
 #' @rdname act_tbl
 summary.act_tbl <- function(object,
@@ -158,15 +158,16 @@ summary.act_tbl <- function(object,
   # If we have elevation, add AvgElev, ElevGain and ElevLoss
   if ("ele" %in% colnames(object)) {
     # We use a rolling 30 second average of elevation to smooth out jitter.
-    period <- min(30, nrow(object))
+    period <- dseconds(min(15, nrow(object)))
     elev_df <- object %>%
       mutate(
-        ele = slidify(
+        ele = slide_index_dbl(
+          .data$ele,
+          .data$time,
           mean,
-          .period = period,
-          .align = "center",
-          .partial = TRUE
-        )(.data$ele)
+          .before = period,
+          .after = period
+        )
       ) %>%
       mutate(
         elevdelta = .data$ele - lag(.data$ele),

tests/testthat/test_act_tbl.R

@@ -29,8 +29,8 @@ test_that("summary works", {
   expect_equal(as.integer(s$MaxPace), 356)
 
   expect_equal(as.integer(s$AvgElev), 765)
-  expect_equal(as.integer(s$ElevGain), 382)
-  expect_equal(as.integer(s$ElevLoss), 54)
+  expect_equal(as.integer(s$ElevGain), 1640)
+  expect_equal(as.integer(s$ElevLoss), 984)
 })
 
 test_that("summary allows use of full to fill in missing columns", {
@@ -76,8 +76,8 @@ test_that("summary allows for metric system", {
   expect_equal(as.integer(s$MaxPace), 221)
 
   expect_equal(as.integer(s$AvgElev), 233)
-  expect_equal(as.integer(s$ElevGain), 116)
-  expect_equal(as.integer(s$ElevLoss), 16)
+  expect_equal(as.integer(s$ElevGain), 500)
+  expect_equal(as.integer(s$ElevLoss), 300)
 })
 
 test_that("summary includes hr when provided", {