barComponent.css

.bar {
    fill: steelblue;
}
a:hover {
    text-decoration: none;    
}
a.active {
    color: maroon;
    font-size: 18px;    
}

.axis path {
    fill: none;
}

barComponent.hbs

<script type="text/x-handlebars" data-template-name='application'>
    <h3> Application Template</h3>
    {{#link-to 'chart'}}Charts{{/link-to}}
    {{#link-to 'normal'}}Normal{{/link-to}}
    {{outlet}}
</script>

<script type="text/x-handlebars" data-template-name='chart'>
    <h3> Chart Template</h3>
    {{bar-chart content=content}}
</script>

<script type="text/x-handlebars" data-template-name='normal'>
    <h3> Normal Template</h3>
</script>

<script type="text/x-handlebars" data-template-name='components/bar-chart'>
    {{yield}}
</script>

barComponent.js

var App = window.App = Em.Application.create();

App.Router.map(function(){
    this.resource('chart', {path: '/'}); 
   this.resource('normal');
});

App.ChartRoute = Em.Route.extend({
    model: function(){
        return chartData;
    }
});

App.NormalRoute = Em.Route.extend({});

App.BarChartComponent = Em.Component.extend({
    drawChart: function(){
    var data = this.get('content');
  var margin = {top: 20, right: 20, bottom: 30, left: 40},
    width = 560 - margin.left - margin.right,
    height = 300 - margin.top - margin.bottom;


var x = d3.scale.ordinal()
    .rangeRoundBands([0, width], .1);

var y = d3.scale.linear()
    .range([height, 0]);

var xAxis = d3.svg.axis()
    .scale(x)
    .orient("bottom");

var yAxis = d3.svg.axis()
    .scale(y)
    .orient("left");
        
var svg = d3.select('#'+this.elementId).append("svg")
    .attr("width", width + margin.left + margin.right)
    .attr("height", height + margin.top + margin.bottom)
  .append("g")
    .attr("transform", "translate(" + margin.left + "," + margin.top + ")");

  x.domain(data.map(function(d) { return d.letter; }));
  y.domain([0, d3.max(data, function(d) { return d.frequency; })]);

  svg.append("g")
      .attr("class", "x axis")
      .attr("transform", "translate(0," + height + ")")
      .call(xAxis);

  svg.append("g")
      .attr("class", "y axis")
      .call(yAxis);

  var bars = svg.selectAll(".bar")
      .data(data)
  
  bars
    .enter().append("rect")
      .attr("class", "bar")
      .attr("x", function(d) { return x(d.letter); })
      .attr("width", x.rangeBand())
      .attr("y", function(d) { return y(0); })
      .attr("height",0)
  .on('mouseover', function(d,i){
     console.log('mouseenter');
      
  })
  .on('mouseout', function(d,i){
      console.log('mouseout');
  });

        bars
        .transition()
        .duration(1500)
          .attr("y", function(d) { return y(d.frequency); })
        .attr('height',  function(d) { return height - y(d.frequency); })
        
    }.on('didInsertElement')
});

var chartData = [
    {letter: 'A', frequency: 10 },
    {letter: 'B', frequency: 5 },
    {letter: 'C', frequency: 8 },
    {letter: 'D', frequency: 2 }]