Demo of how to link shiny to javascript (D3 here) and have cumulative data transfer

d3widget.js

<script src="http://d3js.org/d3.v3.js"></script>
<script type="text/javascript">
(function(){
  // Probably not idiomatic javascript.

  this.countValue=42;
  
  updateView = function(message) {
    
    var svg = d3.select(".d3io").select("svg")

    svg.append("text")
      .transition()
      .attr("x",message[0])
      .attr("y",message[1])
      .text(countValue)
      .each("end",function(){
        countValue+=1;
        $(".d3io").trigger("change");
      })
  }
  
  var d3OutputBinding = new Shiny.OutputBinding();
  $.extend(d3OutputBinding, {
    find: function(scope) {
      return $(scope).find(".d3io");
    },
    renderError: function(el,error) {
      console.log("Foe");
    },
    renderValue: function(el,data) {
      updateView(data);
      console.log("Friend");
      
    }
  });
  Shiny.outputBindings.register(d3OutputBinding);
  
  var d3InputBinding = new Shiny.InputBinding();
  $.extend(d3InputBinding, {
    find: function(scope) {
      return $(scope).find(".d3io");
    },
    getValue: function(el) {
      return countValue;
    },
    subscribe: function(el, callback) {
      $(el).on("change.d3InputBinding", function(e) {
        callback();
      });
    }
  });
  Shiny.inputBindings.register(d3InputBinding);

  
})()
</script>

server.R

library(shiny)

# Define server logic required to respond to d3 requests
shinyServer(function(input, output) {
  
  # Generate a plot of the requested variable against mpg and only 
  # include outliers if requested
  output$d3io <- reactive(function() {
    if (is.null(input$d3io)) {
      0;
    } else {
      list(rnorm(1)*400+200,rnorm(1)*400+200);
    }
  })
})

ui.R

library(shiny)

d3IO <- function(inputoutputID) {
  div(id=inputoutputID,class=inputoutputID,tag("svg",""));
}

# Define UI for shiny d3 chatter application
shinyUI(pageWithSidebar(
  
  # Application title
  headerPanel("D3 Javascript chatter",
              "Demo of how to create D3 I/O and cumulative data transfer"),
  
  # Sidebar with controls to select the variable to plot against mpg
  # and to specify whether outliers should be included
  sidebarPanel(
    tags$p("This widget is a demonstration of how to wire shiny direct to javascript, without any input elements."),
    tags$p("Each time a transition ends, the client asks the server for another packet of information, and adds it
            to the existing set"),
    tags$p("I can't claim this is likely to be idiomatic javascript, because I'm a novice, but it allows d3 apps
            to do progressive rendering.  In real use, a more complex request/response protocol will probably be
            required.  -AlexBBrown")
  ),
  
  mainPanel(
    includeHTML("d3widget.js"),
    d3IO("d3io")
    )
))