D3.js - Bar Chart & Sorting

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

by Simon060694

HTML

<script src="http://d3js.org/d3.v3.min.js"></script>
<body>
    <button id="sort" onclick="sortBars()">Sort</button>
    <button id="reset" onclick="reset()">Reset</button>
</body>

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 = 8000;
var h = 6050;

var dataset = [ 
	{ key: 0, value: 5 },
	{ key: 1, value: 10 },
	{ key: 2, value: 13 }, ];

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)
      .attr('viewbox', `0 0 `);

//Create bars
svg.selectAll("rect")
   .data(dataset, key)
   .enter()
   .append("rect")
   .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 "rgb(0, 0, " + (d.value * 10) + ")";
   })

	//Tooltip
	.on("mouseover", function(d) {
		//Get this bar's x/y values, then augment for the tooltip
		var xPosition = parseFloat(d3.select(this).attr("x")) + xScale.rangeBand() / 2;
		var yPosition = parseFloat(d3.select(this).attr("y")) + 14;
		
		//Update Tooltip Position & value
		d3.select("#tooltip")
			.style("left", xPosition + "px")
			.style("top", yPosition + "px")
			.select("#value")
			.text(d.value);
		d3.select("#tooltip").classed("hidden", false)
	})
	.on("mouseout", function() {
		//Remove the tooltip
		d3.select("#tooltip").classed("hidden", true);
	})	;

//Create labels
svg.selectAll("text")
   .data(dataset, key)
   .enter()
   .append("text")
   .text(function(d) {
		return d.value;
   })
   .attr("text-anchor", "middle")
   .attr("x", function(d, i) {
		return xScale(i) + xScale.rangeBand() / 2;
   })
   .attr("y", function(d) {
		return h - yScale(d.value) + 14;
   })
   .attr("font-family", "sans-serif") 
   .attr("font-size", "11px")
   .attr("fill", "white");
   
var sortOrder = false;
var sortBars = function () {
   ...