anchor.diff:    return 0;
   }
   
  -var preview = false;
  +var is_preview = false;
   function update_data() {
     hide_percent();
     total_amount = 0;
  
positive.code:   data.sort(compare_categories);
  
    /* ------- PREVIEW IF NO DATA -------*/
    // data = [];
    if (data.length == 0) {
      preview = true;
      data = [
        {amount:165.34, category:"Groceries", amount_str:"$165.34"},
        {amount:110.07, category:"Bills",     amount_str:"$110.07"},
  
negative.code:   .attr("font-size", "1.5em")
    .attr("fill", "gray");
  svg.append("g")
    .attr("class", "no_data")
    .style("visibility", "hidden")
    .append("text")
      .text("No Results")
      .attr("dy", ".4em")
      .style("text-anchor", "middle")
      .style("font-size", "1.9em");
  previewLabel = svg.append("g")
    .attr("class", "preview")
    .style("visibility", "hidden");
  
  previewLabel
    .append("rect")
      .attr("x", -width / 2)
      .attr("y", -height / 2)
      .attr("width", width)
      .attr("height", height)
      .attr("fill", "white")
      .attr("opacity", 0.75);
  previewLabel
    .append("text")
      .text("Preview")
      .attr("dy", ".4em")
      .style("text-anchor", "middle")
      .style("font-size", "1.9em");
  
  
  
  
  var color = d3.scale.category20();
  
  