Updated d3v4 fiddle not working - d3.js

Question

I am upgrading this d3v3 pie chart code into d3v4 pie chart. But it is not working. Any insight would be highly appreciated.
v4 fiddle
The code is pretty much the same apart from these few changes i have made:
var pie = d3.pie()
var arc = d3.arc()
var outerarc = d3.arc()

Answer 1

In D3 v4.x, there is no more the magic of the enter().append, which changes the update selection in v3.x.
Now, you have to merge the selections:
//here you bind the data. This is the "update" selection
var slice = svg.select(".slices").selectAll("path.slice")
.data(pie(data), key);
//now comes your enter selection
slice.enter()
.append("path")
.attr("class", "slice")
.merge(slice)//from now on, "enter" + "update" selections
.style("fill", function(d) {
return color(d.data.label);
})
.transition().duration(1000)
.attrTween("d", function(d) {
this._current = this._current || d;
var interpolate = d3.interpolate(this._current, d);
this._current = interpolate(0);
return function(t) {
return arc(interpolate(t));
};
})
Here is your code with the merged selections:
var svg = d3.select("body")
.append("svg")
.append("g")
svg.append("g")
.attr("class", "slices");
svg.append("g")
.attr("class", "labels");
svg.append("g")
.attr("class", "lines");
var width = 960,
height = 450,
radius = Math.min(width, height) / 2;
var pie = d3.pie()
.sort(null)
.value(function(d) {
return d.value;
});
var arc = d3.arc()
.outerRadius(radius * 0.8)
.innerRadius(radius * 0.4);
var outerArc = d3.arc()
.innerRadius(radius * 0.9)
.outerRadius(radius * 0.9);
svg.attr("transform", "translate(" + width / 2 + "," + height / 2 + ")");
var key = function(d) {
return d.data.label;
};
var color = d3.scaleOrdinal()
.domain(["Lorem ipsum", "dolor sit", "amet", "consectetur", "adipisicing", "elit", "sed", "do", "eiusmod", "tempor", "incididunt"])
.range(["#98abc5", "#8a89a6", "#7b6888", "#6b486b", "#a05d56", "#d0743c", "#ff8c00"]);
function randomData() {
var labels = color.domain();
return labels.map(function(label) {
return {
label: label,
value: Math.random()
}
});
}
change(randomData());
d3.select("button")
.on("click", function() {
change(randomData());
});
function change(data) {
/* ------- PIE SLICES -------*/
var slice = svg.select(".slices").selectAll("path.slice")
.data(pie(data), key);
slice.enter()
.append("path")
.attr("class", "slice")
.merge(slice)
.style("fill", function(d) {
return color(d.data.label);
})
.transition().duration(1000)
.attrTween("d", function(d) {
this._current = this._current || d;
var interpolate = d3.interpolate(this._current, d);
this._current = interpolate(0);
return function(t) {
return arc(interpolate(t));
};
})
slice.exit()
.remove();
/* ------- TEXT LABELS -------*/
var text = svg.select(".labels").selectAll("text")
.data(pie(data), key);
function midAngle(d) {
return d.startAngle + (d.endAngle - d.startAngle) / 2;
}
text.enter()
.append("text")
.attr("dy", ".35em")
.text(function(d) {
return d.data.label;
}).merge(text)
.transition().duration(1000)
.attrTween("transform", function(d) {
this._current = this._current || d;
var interpolate = d3.interpolate(this._current, d);
this._current = interpolate(0);
return function(t) {
var d2 = interpolate(t);
var pos = outerArc.centroid(d2);
pos[0] = radius * (midAngle(d2) < Math.PI ? 1 : -1);
return "translate(" + pos + ")";
};
})
.styleTween("text-anchor", function(d) {
this._current = this._current || d;
var interpolate = d3.interpolate(this._current, d);
this._current = interpolate(0);
return function(t) {
var d2 = interpolate(t);
return midAngle(d2) < Math.PI ? "start" : "end";
};
});
text.exit()
.remove();
/* ------- SLICE TO TEXT POLYLINES -------*/
var polyline = svg.select(".lines").selectAll("polyline")
.data(pie(data), key);
polyline.enter()
.append("polyline")
.merge(polyline)
.transition().duration(1000)
.attrTween("points", function(d) {
this._current = this._current || d;
var interpolate = d3.interpolate(this._current, d);
this._current = interpolate(0);
return function(t) {
var d2 = interpolate(t);
var pos = outerArc.centroid(d2);
pos[0] = radius * 0.95 * (midAngle(d2) < Math.PI ? 1 : -1);
return [arc.centroid(d2), outerArc.centroid(d2), pos];
};
});
polyline.exit()
.remove();
};
body {
font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
width: 960px;
height: 500px;
position: relative;
}
svg {
width: 100%;
height: 100%;
}
path.slice {
stroke-width: 2px;
}
polyline {
opacity: .3;
stroke: black;
stroke-width: 2px;
fill: none;
}
<script src="https://d3js.org/d3.v4.min.js"></script>
<button>Randomize</button>