Implement default selection for filter_select

Fixes #35

DESCRIPTION

@@ -1,7 +1,7 @@
 Package: crosstalk
 Type: Package
 Title: Inter-Widget Interactivity for HTML Widgets
-Version: 1.0.1
+Version: 1.0.1.9000
 Authors@R: c(
     person("Joe", "Cheng", role = c("aut", "cre"), email = "[email protected]"),
     person(family = "RStudio", role = "cph"),

NEWS.md

@@ -1,3 +1,7 @@
+## crosstalk 1.0.1.9000
+
+* Add `selected` parameter to `filter_select`, to specify default selection.
+
 ## crosstalk 1.0.1
 
 * `selection_factor` behavior was no longer correct with ggplot2 2.2.0, which

R/controls.R

@@ -59,7 +59,7 @@ ionrangesliderLibs <- function() {
   )
 }
 
-makeGroupOptions <- function(sharedData, group, allLevels) {
+makeGroupOptions <- function(sharedData, group, allLevels, selected = NULL) {
   df <- sharedData$data(
     withSelection = FALSE,
     withFilter = FALSE,
@@ -89,10 +89,23 @@ makeGroupOptions <- function(sharedData, group, allLevels) {
 
   lvls_str <- as.character(lvls)
 
+  if (!is.null(selected)) {
+    selected <- unique(as.character(selected))
+    present <- selected %in% lvls_str
+    if (any(!present)) {
+      warning(call. = FALSE,
+        "Default selection was specified that was not present in the data [",
+        paste0("'", selected[!present], "'", collapse = ","),
+        "]"
+      )
+      selected <- selected[present]
+    }
+  }
   options <- list(
     items = data.frame(value = lvls_str, label = lvls_str, stringsAsFactors = FALSE),
     map = setNames(vals, lvls_str),
-    group = sharedData$groupName()
+    group = sharedData$groupName(),
+    selected = selected
   )
 
   options
@@ -114,6 +127,7 @@ makeGroupOptions <- function(sharedData, group, allLevels) {
 #'   present in the data?
 #' @param multiple Can multiple values be selected?
 #' @param columns Number of columns the options should be arranged into.
+#' @param selected Default value(s) to be selected.
 #'
 #' @examples
 #' ## Only run examples in interactive R sessions
@@ -126,9 +140,16 @@ makeGroupOptions <- function(sharedData, group, allLevels) {
 #'
 #' @export
 filter_select <- function(id, label, sharedData, group, allLevels = FALSE,
-  multiple = TRUE) {
+  multiple = TRUE, selected = NULL) {
 
-  options <- makeGroupOptions(sharedData, group, allLevels)
+  if (!multiple && length(selected) > 1) {
+    warning(call. = FALSE, "filter_select called with multiple=FALSE ",
+      "but more than one selected value; only the first element will ",
+      "be used")
+    selected <- selected[[1]]
+  }
+
+  options <- makeGroupOptions(sharedData, group, allLevels, selected)
 
   htmltools::browsable(attachDependencies(
     tags$div(id = id, class = "form-group crosstalk-input-select crosstalk-input",

javascript/src/input_selectize.js

@@ -18,6 +18,7 @@ input.register({
     let items = util.dataframeToD3(data.items);
     let opts = {
       options: first.concat(items),
+      items: data.selected,
       valueField: "value",
       labelField: "label",
       searchField: "label"
@@ -30,7 +31,7 @@ input.register({
     let ctHandle = new FilterHandle(data.group);
 
     let lastKnownKeys;
-    selectize.on("change", function() {
+    function updateFilter() {
       if (selectize.items.length === 0) {
         lastKnownKeys = null;
         ctHandle.clear();
@@ -46,7 +47,9 @@ input.register({
         lastKnownKeys = keyArray;
         ctHandle.set(keyArray);
       }
-    });
+    }
+    selectize.on("change", updateFilter);
+    updateFilter();
 
     return {
       suspend: function() {