D3 Gauge

HTML

<script src="https://d3js.org/d3.v2.min.js"></script>
<div id="power-gauge"></div>

CSS

body {
		font-family:  Helvetica, Arial, sans-serif;
		margin: 32px;
	}

	#power-gauge g.arc {
		fill: #ccc;
	}

	#power-gauge g.pointer {
		fill: #ffbe00;
		stroke: #ffbe00;
	}
	
	#power-gauge g.label text {
		text-anchor: middle;
		font-size: 12px;
		font-weight: bold;
		fill: #666;
	}

JavaScript

var gauge = function(container, configuration) {
	var that = {};
	var config = {
		size						: 200,
		clipWidth					: 200,
		clipHeight					: 110,
		ringInset					: 20,
		ringWidth					: 20,
		
		pointerWidth				: 10,
		pointerTailLength			: 5,
		pointerHeadLengthPercent	: 0.7,
		
		minValue					: 0,
		maxValue					: 10,
		
		minAngle					: -90,
		maxAngle					: 90,
		
		transitionMs				: 750,
		
		majorTicks					: 5,
		labelFormat					: d3.format(',g'),
		labelInset					: 10,
		
        arcColorFn					:   d3.scale.quantize()
                                        .domain([0, 0.166, 0.332, 0.498, 0.664, 0.830, 1])
                                        .range(['#FFCE00','#FFCE00','#42BF8E','#42BF8E','#42BF8E', '#FD606A'])
	};
	var range = undefined;
	var r = undefined;
	var pointerHeadLength = undefined;
	var value = 0;
	
	var svg = undefined;
	var arc = undefined;
	var scale = undefined;
	var ticks = undefined;
	var tickData = undefined;
	var pointer = undefined;

	var donut = d3.layout.pie();
	
	function deg2rad(deg) {
		return deg * Math.PI / 180;
	}
	
	function newAngle(d) {
		var ratio = scale(d);
		var newAngle = config.minAngle + (ratio * range);
		return newAngle;
	}
	
	function configure(configuration) {
		var prop = undefined;
		for ( prop in configuration ) {
			config[prop] = configuration[prop];
		}
		
		range = config.maxAngle - config.minAngle;
		r = config.size / 2;
		pointerHeadLength = Math.round(r * config.pointerHeadLengthPercent);

		// a linear scale that maps domain values to a percent from 0..1
		scale = d3.scale.linear()
			.range([0,1])
			.domain([config.minValue, config.maxValue]);
			
		ticks = scale.ticks(config.majorTicks);
		tickData = d3.range(config.majorTicks).map(function() {return 1/config.majorTicks;});
		
		arc = d3.svg.arc()
			.innerRadius(r - config.ringWidth - config.ringInset)
			.outerRadius(r - config.ringInset)
			.startAngle(function(d, i) {
				var ratio = d * i;
				return deg2rad(config.minAngle + (ratio *...