First attempt at getting crosstalk to work.

.gitignore

@@ -1,3 +1,4 @@
 .Rproj.user
 .Rhistory
 .RData
+inst/doc

DESCRIPTION

@@ -13,3 +13,6 @@ Imports:
   crosstalk,
   htmltools,
   htmlwidgets
+Suggests: knitr,
+    rmarkdown
+VignetteBuilder: knitr

R/summarywidget.R

@@ -48,6 +48,7 @@ summarywidget <- function(data,
     if (!is.logical(selection))
       stop("Selection must contain TRUE/FALSE values.")
     data = data[selection,]
+    key = key[selection]
   }
 
   # We just need one column, either the row.names or the specified column.
@@ -111,3 +112,8 @@ renderSummarywidget <- function(expr, env = parent.frame(), quoted = FALSE) {
   if (!quoted) { expr <- substitute(expr) } # force quoted
   htmlwidgets::shinyRenderWidget(expr, summarywidgetOutput, env, quoted = TRUE)
 }
+
+# Use a <span> container rather than the default <div>
+summarywidget_html <- function(id, style, class, ...){
+  htmltools::tags$span(id = id, class = class)
+}

inst/htmlwidgets/summarywidget.js

@@ -6,25 +6,62 @@ HTMLWidgets.widget({
 
   factory: function(el, width, height) {
 
-    return {
+    filterKeys = function(obj, keys) {
+      var result = {};
+      keys.forEach(function(k) { result[k]=obj[k];});
+    };
 
+    return {
       renderValue: function(x) {
+
+        // Make a data object with keys
+        var data = {};
+        var i;
+        if (x.settings.crosstalk_key === null) {
+          for (i=0; i<x.data.length; i++) {
+            data[i] = x.data[i];
+          }
+        } else {
+          for (i=0; i<x.settings.crosstalk_key.length; i++) {
+            data[x.settings.crosstalk_key[i]] = x.data[i];
+          }
+        }
+
+        update = function(d) {
+          // Get a simple vector. Don't use Object.values(), RStudio doesn't seem to support it.
+          var values = [];
+          for (var key in d) {
+            if (d.hasOwnProperty(key)) { values.push(d[key]);}
+          }
+
         var value = 0;
         switch (x.settings.statistic) {
           case 'count':
-            value = x.data.length;
+            value = values.length;
             break;
           case 'sum':
-            value = x.data.reduce(function(acc, val) {return acc + val;}, 0);
+            value = values.reduce(function(acc, val) {return acc + val;}, 0);
             break;
           case 'mean':
-            value = x.data.reduce(function(acc, val) {return acc + val;}, 0) / x.data.length;
+            value = values.reduce(function(acc, val) {return acc + val;}, 0) / values.length;
             break;
         }
 
         if (x.settings.digits !== null) value = value.toFixed(x.settings.digits);
         el.innerText = value;
+       };
+
+       var ct_sel = new crosstalk.SelectionHandle();
+       ct_sel.setGroup(x.settings.crosstalk_group);
+       ct_sel.on("change", function(e) {
+         if (e.value && e.value.length) {
+           update(filterKeys(data, e.value));
+         } else {
+           update(data);
+         }
+       });
 
+       update(data);
       },
 
       resize: function(width, height) {

vignettes/Using summarywidget.Rmd

@@ -0,0 +1,30 @@
+---
+title: "Using summarywidget"
+author: "Kent S Johnson"
+date: "`r Sys.Date()`"
+output: rmarkdown::html_vignette
+vignette: >
+  %\VignetteIndexEntry{Using summarywidget}
+  %\VignetteEngine{knitr::rmarkdown}
+  %\VignetteEncoding{UTF-8}
+---
+
+```{r}
+library(crosstalk)
+library(DT)
+library(summarywidget)
+
+shared_mtcars = SharedData$new(mtcars[,c("mpg", "cyl", "hp", "am")])
+
+summarywidget(shared_mtcars)
+
+bscols(widths = c(3,NA),
+  list(
+    filter_checkbox("cyl", "Cylinders", shared_mtcars, ~cyl, inline = TRUE),
+    filter_slider("hp", "Horsepower", shared_mtcars, ~hp, width = "100%")
+  ),
+  datatable(shared_mtcars, width=600)
+)
+```
+
+