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@Fil
Last active Dec 8, 2016
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events and ES6 arrow functions [UNLISTED]
license: mit
<!DOCTYPE html>
<head>
<meta charset="utf-8">
<script src="https://d3js.org/d3.v4.min.js"></script>
<style>
body { margin:0;position:fixed;top:0;right:0;bottom:0;left:0; }
</style>
</head>
<body>
<script>
// Feel free to change or delete any of the code you see in this editor!
var svg = d3.select("body").append("svg")
.attr("width", 960)
.attr("height", 500)
// With regular functions I use _this_ to react to an event
svg.selectAll('text')
.data([1,2])
.enter()
.append("text")
.text((d) => "hover me " + d)
.attr("y", (d,i) => 110 + 50 * i)
.attr("x", 120)
.style("font-size", 36)
.style("font-family", "monospace")
.on('mousemove', function() {
d3.select(this)
.text(Math.random()).attr('fill', 'blue')
}
);
// With arrow functions, _this_ is not available, and I need to add an id
svg.selectAll('text')
.data([1,2,3,4])
.enter()
.append("text")
.attr('id', (d,i) => "data-" + i)
.text((d) => "hover me " + d)
.attr("y", (d,i) => 130 + 50 * i)
.attr("x", 120)
.style("font-size", 36)
.style("font-family", "monospace")
.on('mousemove', (d,i) =>
svg.select("#data-" + i)
.text(Math.random()).attr('fill', 'green')
);
// d3.event.target to the rescue
svg.selectAll('text')
.data([1,2,3,4,5,6])
.enter()
.append("text")
.text((d) => "hover me " + d)
.attr("y", (d,i) => 150 + 50 * i)
.attr("x", 120)
.style("font-size", 36)
.style("font-family", "monospace")
.on('mousemove', () => d3.select(d3.event.target)
.text(Math.random()).attr('fill', 'red')
);
</script>
</body>
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