Q:

D3 / design - bar graph,seeking snazzy way to indicate "N/A"

Somebody's got to have a smart idea for this.
I've got a great bar graph with some N/A values, like for Vermont. So no bar is drawn for Vermont. Great! But I'd like to append "N/A" just to the right of the word Vermont, or some kind of indication that Vermont is an N/A. Otherwise, it possibly looks like a mistake, like "Hey, where is Vermont's data? Why is there a blank spot here?" 
http://bl.ocks.org/greencracker/raw/4f7ff98cea98413ef5f4/
Key block is this:
  barUpdate.select("rect")   
  .attr("width", function (d) { return x(d[age]);}) //< -- need something here?
  .attr("fill", function (d) {
    if (d.State == "Georgia") {return "goldenrod";} 
    else {return color(age); } ;})
  .attr("fill-opacity", function (d) {
    if (d.State == "United States") {return 0.6;} ;});

I would think something like this … ?
.attr("width", function (d) { if (x(d[age])) == 0) {this.append("umm? something here?");}
{x(d[age]);} 

I know I can't append "text" to a "rect".  I've fiddled with this.append("g").append("text") but no luck.  

A:

I'm not sure that I would use N/A, as it can be ambiguous.  Does it mean Not Applicable or Not Available.  They are subtle differences, for sure, but it might be worth selecting a different phrase to indicate a lack of data.
That said...  You can easily just add a new text element for each data item that you've got, and just set it to "" for the states that have data and "N/A" for those that don't.
I've forked your gist and come up with this: http://bl.ocks.org/benlyall/361716dbd79f13488a4e
The extra code that I've added is:
barEnter.append("text")
        .attr("class", "value-label")
        .attr("x", -3)
        .attr("y", y.rangeBand() / 2)
        .attr("dy", ".35em")
        .attr("text-anchor", "start");

...

barUpdate.select("text.value-label")
         .attr("x", function(d) {
             return x(d[age]);
         })
         .text(function(d) {
             if (d[age] == "") {
                 return "N/A";
             } else {
                 return "";
             }
         });

You'll obviously end up with additional text elements in your SVG, it's up to you to decide if that matters to you or not.

