D3.js - Bar Chart & Sorting

Use D3.js to sort in ascending & descending order, utilizing JS Objects.

HTML

<script src="http://d3js.org/d3.v3.min.js"></script>

CSS

.axis path,
.axis line {
	fill: none;
	stroke: black;
	shape-rendering: crispEdges;
}
.axis text {
	font-family: sans-serif;
	font-size: 11px;
}

rect {
	-moz-transition: all 0.3s;
	-webkit-transition: all 0.3s;
	-o-transition: all 0.3s;
	transition: all 0.3s;
}
rect:hover{
	fill: orange;
}

JavaScript

var w = 600;
var h = 250;

var dataset = [ 
	{ key: 0, value: 5 },
	{ key: 1, value: 10 },
	{ key: 2, value: 13 },
	{ key: 3, value: 19 },
	{ key: 4, value: 21 },
	{ key: 5, value: 25 },
	{ key: 6, value: 22 },
	{ key: 7, value: 18 },
	{ key: 8, value: 15 },
	{ key: 9, value: 13 },
	{ key: 10, value: 11 },
	{ key: 11, value: 12 },
	{ key: 12, value: 15 },
	{ key: 13, value: 20 },
	{ key: 14, value: 18 },
	{ key: 15, value: 17 },
	{ key: 16, value: 16 },
	{ key: 17, value: 18 },
	{ key: 18, value: 23 },
	{ key: 19, value: 25 } ];

var xScale = d3.scale.ordinal()
				.domain(d3.range(dataset.length))
				.rangeRoundBands([0, w], 0.05); 

var yScale = d3.scale.linear()
				.domain([0, d3.max(dataset, function(d) {return d.value;})])
				.range([0, h]);

var key = function(d) {
	return d.key;
};

//Create SVG element
var svg = d3.select("body")
			.append("svg")
			.attr("width", w)
			.attr("height", h);

//Create bars
svg.selectAll("rect")
   .data(dataset, key)
   .enter()
   .append("rect")
   .attr("id", function(d,i){return "rect"+i;})
   .attr("x", function(d, i) {
		return xScale(i);
   })
   .attr("y", function(d) {
		return h - yScale(d.value);
   })
   .attr("width", xScale.rangeBand())
   .attr("height", function(d) {
		return yScale(d.value);
   })
   .attr("fill", function(d) {
		return "blue";
   })

	//Tooltip
	.on("mouseover", function(d) {
		d3.select(this).style("fill","red");
	})
	.on("mouseout", function() {
		d3.select(this).style("fill","blue");
	})	;
  var z = 0;
  var timeoutFunc = function(){ 
  setTimeout(function(){
  	if(z < 20){
      d3.select("#rect"+ z).transition().duration(350).attr("fill","red")
      .transition().delay(550).attr("fill","blue");      
      z++;
      timeoutFunc();
    }else if(z == 20){
    	z = 0;
      timeoutFunc();
    }    
  },1000);
  };
  
  timeoutFunc();

//Create labels
svg.selectAll("text")
   .data(dataset, key)
   .enter()
   .append("text")
   .text(function(d) {
		return d.value;
   })
  ...