This example demonstrates how to animate a path and a clipped textPath at the same time.
<!DOCTYPE html>
<meta charset="utf-8">
<style>
path {
fill: #3182bd;
}
text {
font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
font-size: 24px;
}
</style>
<body>
<script src="//d3js.org/d3.v3.min.js"></script>
<script>
var arc = d3.svg.arc()
.innerRadius(180)
.outerRadius(220)
.startAngle(0)
.endAngle(function(t) { return t * 2 * Math.PI / 3; });
var svg = d3.select("body").append("svg")
.attr("width", 960)
.attr("height", 500)
.append("g")
.attr("transform", "translate(480,250)");
svg.append("defs").append("path")
.attr("id", "text-path")
.attr("d", arc(1));
svg.append("path")
.attr("id", "path");
svg.append("clipPath")
.attr("id", "text-clip")
.append("use")
.attr("xlink:href", "#path");
svg.append("text")
.attr("clip-path", "url(#text-clip)")
.attr("x", 8)
.attr("dy", 28)
.append("textPath")
.attr("xlink:href", "#text-path")
.text("Hello, curved textPath!");
d3.select("#path").transition()
.duration(5000)
.attrTween("d", function() { return arc; });
</script>