<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>General Update Pattern</title>
<script src="https://d3js.org/d3.v7.js"></script>
</head>
<body>
<script>
// Create svg and initial bars
const svg = d3.select("body")
.append("svg")
.attr("width", "500")
.attr("height", "400");
const bardata = [300, 100, 150, 225, 75, 275];
const bars = svg.selectAll("rect")
.data(bardata);
bars.enter().append("rect")
.attr("x", "30")
.attr("y", (d, i) => i*50)
.attr("width", d => d)
.attr("height", "35")
.attr("fill", "lightgreen");
// General Update Pattern
function update(data) {
const bars = svg.selectAll("rect") // data join
.data(data);
bars.enter()
.append("rect") // add new elements
.attr("x", "30")
.attr("y", (d, i) => i*50)
.attr("width", d => d)
.attr("height", "35")
.attr("fill", "yellow")
.merge(bars) // merge
.transition()
.duration(2000)
.attr("width", d => d)
.attr("fill", "orange");
bars.exit().remove(); // remove extra elements
}
</script>
</body>
</html>