title: Error: <rect> attribute width: Expected length, "NaN". and <text> attribute dx: Expected length, "NaN"
body: <p>I want to implement a bar chart in D3,  but my values on the dx axis are of type Date, data type which the D3 library should accept, but it seems to give me an error like this:  attribute width: Expected length, "NaN".
  This is my code:</p>
  
  <pre><code>&lt;html&gt; 
   &lt;head&gt; 
      &lt;meta charset="utf-8"&gt;         
      &lt;title&gt;a bar graph&lt;/title&gt; 
   &lt;/head&gt; 
   &lt;style&gt;
      .axis path,
      .axis line{
          fill: none;
          stroke: black;
          shape-rendering: crispEdges;
      }
  
      .axis text {
          font-family: sans-serif;
          font-size: 11px;
      }
  
      .MyRect {
          fill: steelblue;
      }
  
      .MyText {
          fill: white;
          text-anchor: middle;
      }
   &lt;/style&gt;
      &lt;body&gt;
          &lt;script src="http://d3js.org/d3.v4.min.js" charset="utf-8"&gt;&lt;/script&gt;
          &lt;script&gt;
          var width=400;  
          var height=400; 
  
          var svg=d3.select("body")  
                    .append("svg")  
                    .attr("width",width)  
                    .attr("height",height); 
  
          var padding = {left:30, right:30, top:20, bottom:20};
  
          var dataset=[10,20,30,40,33,24,12,5]; 
  
  
          var xScale = d3.scaleBand()
                         .domain(d3.range(dataset.length))
                         .range([0, width-padding.left-padding.right]);
  
  
          var yScale = d3.scaleLinear()
                         .domain([0,d3.max(dataset)])
                         .range([height-padding.top-padding.bottom,0]);
  
          var xAxis = d3.axisBottom()
                        .scale(xScale)          
  
          var yAxis = d3.axisLeft()
                        .scale(yScale)
  
          var rectPadding=4;  
  
          var rects = svg.selectAll(".Myrect")
                         .data(dataset)
                         .enter()
                         .append("rect")
                         .attr("class","Myrect")
                         .attr("transform","translate(" + padding.left + "," + padding.top + ")")
                         .attr("x",function(d,i){
                              return xScale(i) + rectPadding/2;
                          })
                          .attr("y",function(d){
                              return yScale(d);
                          })
                         .attr("width",xScale.range()- rectPadding)
                         .attr("height",function(d){
                              return height - padding.top - padding.bottom - yScale(d);
                         });
          var texts = svg.selectAll(".MyText")
                         .data(dataset)
                         .enter()
                         .append("text")
                         .attr("class","MyText")
                         .attr("transform","translate(" + padding.left + "," + padding.top + ")")
                         .attr("x", function(d,i){
                                  return xScale(i) + rectPadding/2;
                          })
                         .attr("y",function(d){
                                  return yScale(d);
                          })
                         .attr("dx",function(){
                                  return (xScale.range() - rectPadding)/2;
                          })
                         .attr("dy",function(d){
                                  return 20;
                          })
                         .text(function(d){
                                  return d;
                          });
  
          svg.append("g")
             .attr("class","axis")
             .attr("transform","translate(" + padding.left + "," + (height - padding.bottom) + ")")
             .call(xAxis); 
  
          svg.append("g")
             .attr("class","axis")
             .attr("transform","translate(" + padding.left + "," + padding.top + ")")
             .call(yAxis);
          &lt;/script&gt;
      &lt;/body&gt; 
  &lt;/html&gt;
  </code></pre>
  
  <p>And the another error:  attribute dx: Expected length, "NaN". I think it arises from band scales, but after using the introduction of the official, it still can't work.
  The introduction of the official:</p>
  
  <pre><code>var x = d3.scaleBand()
      .domain(["a", "b", "c"])
      .range([0, width]);
  </code></pre>
  
  <p>So when I want to call the code, I think it should be used like this in my pasted code:</p>
  
  <pre><code>var texts = svg.selectAll(".MyText")
                         .data(dataset)
                         .enter()
                         .append("text")
                         .attr("class","MyText")
                         .attr("transform","translate(" + padding.left + "," + padding.top + ")")
                         .attr("x", function(d,i){
                                  return xScale(i) + rectPadding/2;
                          })
                         .attr("y",function(d){
                                  return yScale(d);
                          })
                         .attr("dx",function(){
                                  return (xScale.range() - rectPadding)/2;
                          })
                         .attr("dy",function(d){
                                  return 20;
                          })
                         .text(function(d){
                                  return d;
                          });
  </code></pre>
  
  <p>But it seems to give me two errors. I'm a beginner. Thank you very much!</p>