D3 Multiline Chart with Transform Interpolation

<!doctype html>
<html>
<head>
	<meta charset="utf-8">
	<title>Pure D3 Charts</title>

<div>
		<h1>Pure D3</h1>
		<p>
			Using pure d3 for a line chart.
		</p>
		<h2>Line Chart</h2>
		<div id="line-chart"></div>
	</div>

var getIncrementedTimestamp = function(increment) {
			return new Date(2015, 0, 1).getTime() + increment * 60000;
		};

var lastRandom = {};

var getRandomValue = function(series) {
			var options = {
				min: 0,
				max: 2,
				integers: false
			};

var randomize = function() {
				if (lastRandom[series] === undefined || lastRandom[series] === null) {
					lastRandom[series] = Math.random() * Math.abs(options.max - options.min) + options.min;
					return lastRandom[series];
				}
				lastRandom[series] = Math.abs(lastRandom[series] + Math.random() - 0.5);
				return lastRandom[series];
			};

return options.integers ? Math.ceil(randomize()) : randomize();
		};

var NUMBER_OF_TIMESERIES = 2;
		var VALUES_PER_TIMESERIES = 60;

var data = [];

for (var series=0; series<NUMBER_OF_TIMESERIES; series++) {
			data[series] = [];
			for (var dp=0; dp<VALUES_PER_TIMESERIES; dp++) {
				data[series][dp] = {
					timestamp: getIncrementedTimestamp(dp),
					value: getRandomValue(series)
				};
			}
		}

var lineChart = new LineChart();
		lineChart.draw(data);

var currentTS = data[0].length - 1;

window.setInterval(function() {

// remove old data point from start
			if (data[0].length > VALUES_PER_TIMESERIES) {
				data.forEach(function(d) {
					d.shift();
				});
			}

// add new data point to end
			data.forEach(function(d, i) {
				d.push({
					timestamp: getIncrementedTimestamp(currentTS + 1),
					value: getRandomValue(i)
				});
			});
			currentTS++;

// update line
			lineChart.draw(data);

}, 1000);

</script>

</body>
</html>

https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.6/d3.min.js