Trying to link object and text when dragging in v4 - d3.js

Question

I have been trying to learn enough about d3.drag to integrate it into a sankey diagram for v4 similar to this example.
The start point was Mikes circle dragging example here which I tried to integrate with the object+text drag implementation here.
Tragically I can't quite work out how to grab the 'g' element using d3.drag.
There have been several iterations over the past few days, but I think the closest I have come is the example below which will only grab a specific rectangle for dragging (I suspect I may have butchered the use of 'this').
var margin = {top: 10, right: 10, bottom: 30, left: 10},
width = 960 - margin.left - margin.right,
height = 500 - margin.top - margin.bottom;
var rectangles = d3.range(20).map(function() {
return {
x: Math.round(Math.random() * (width)),
y: Math.round(Math.random() * (height))
};
});
var color = d3.scaleOrdinal(d3.schemeCategory20);
var svg = d3.select("body").append("svg")
.attr("width", width + margin.left + margin.right)
.attr("height", height + margin.top + margin.bottom);
var group = svg.append("g")
.data(rectangles)
.attr("transform",
"translate(" + margin.left + "," + margin.top + ")")
.call(d3.drag()
.on("start", dragstarted)
.on("drag", dragged)
.on("end", dragended));
group.selectAll("rect")
.data(rectangles)
.enter().append("rect")
.attr("x", function(d) { return d.x; })
.attr("y", function(d) { return d.y; })
.attr("height", 60)
.attr("width", 30)
.style("fill", function(d, i) { return color(i); });
group.selectAll("text")
.data(rectangles)
.enter().append("text")
.attr("x", function(d) { return d.x; })
.attr("y", function(d) { return d.y; })
.attr("text-anchor", "start")
.style("fill", "steelblue")
.text("Close");
function dragstarted(d) {
d3.select(this).raise().classed("active", true);
}
function dragged(d) {
d3.select(this).select("text").attr("x", d.x = d3.event.x).attr("y", d.y = d3.event.y);
d3.select(this).select("rect").attr("x", d.x = d3.event.x).attr("y", d.y = d3.event.y);
}
function dragended(d) {
d3.select(this).classed("active", false);
}
.active {
stroke: #000;
stroke-width: 2px;
}
.rect {
pointer-events: all;
stroke: none;
stroke-width: 40px;
}
<script src="//d3js.org/d3.v4.min.js"></script>
I tried to implement the code per the answer here which is a close analog, but the changes involved with moving from the force diagram defeated me as well.
Any guidance appreciated. I feel like I'm missing something fundamental.

Answer 1

I tweaked your code a little. I grouped both rectangles and text and added the drag attribute to the group. So, when we drag, both text and rectangle move in sink.
var margin = {top: 10, right: 10, bottom: 30, left: 10},
width = 960 - margin.left - margin.right,
height = 500 - margin.top - margin.bottom;
var rectangles = d3.range(10).map(function() {
return {
x: Math.round(Math.random() * (width)),
y: Math.round(Math.random() * (height))
};
});
var color = d3.scaleOrdinal(d3.schemeCategory20);
var svg = d3.select("body").append("svg")
.attr("width", width + margin.left + margin.right)
.attr("height", height + margin.top + margin.bottom);
var group = svg.selectAll('g')
.data(rectangles).enter().append("g").attr("transform",
"translate(" + margin.left + "," + margin.top + ")")
.call(d3.drag()
.on("start", dragstarted)
.on("drag", dragged)
.on("end", dragended));
group.append("rect")
.attr("x", function(d) { return d.x; })
.attr("y", function(d) { return d.y; })
.attr("height", 60)
.attr("width", 30)
.style("fill", function(d, i) { return color(i); });
group.append("text")
.attr("x", function(d) { return d.x; })
.attr("y", function(d) { return d.y; })
.attr("text-anchor", "start")
.style("fill", "steelblue")
.text("Close");
function dragstarted(d) {
d3.select(this).raise().classed("active", true);
}
function dragged(d) {
d3.select(this).select("text").attr("x", d.x = d3.event.x).attr("y", d.y = d3.event.y);
d3.select(this).select("rect").attr("x", d.x = d3.event.x).attr("y", d.y = d3.event.y);
}
function dragended(d) {
d3.select(this).classed("active", false);
}
.active {
stroke: #000;
stroke-width: 2px;
}
.rect {
pointer-events: all;
stroke: none;
stroke-width: 40px;
}
<script src="//d3js.org/d3.v4.min.js"></script>
Hope this helps.

Answer 2

You can also try this alternative way of grouping and moving groups.
var margin = {top: 10, right: 10, bottom: 30, left: 10},
width = 960 - margin.left - margin.right,
height = 500 - margin.top - margin.bottom;
var rectangles = d3.range(10).map(function() {
return {
x: Math.round(Math.random() * (width)),
y: Math.round(Math.random() * (height))
};
});
var color = d3.scaleOrdinal(d3.schemeCategory20);
var svg = d3.select("body").append("svg")
.attr("width", width + margin.left + margin.right)
.attr("height", height + margin.top + margin.bottom);
var group = svg.selectAll('g')
.data(rectangles)
.enter().append("g")
.attr("transform",function(d) {
return "translate(" + (margin.left + d.x) + "," + (margin.top + d.y) + ")"
})
.call(d3.drag()
.on("start", dragstarted)
.on("drag", dragged)
.on("end", dragended));
group.append("rect")
.attr("height", 60)
.attr("width", 30)
.style("fill", function(d, i) { return color(i); });
group.append("text")
.attr("text-anchor", "start")
.style("fill", "steelblue")
.text("Close");
function dragstarted(d) {
d._drag = {
distance:0,
threshold:2,
initiated: false
};
}
function dragged(d) {
if (!d._drag.initiated) {
d._drag.initiated = true;
d3.select(this).raise().classed("active", true);
}
d._drag.distance += d3.event.dx * d3.event.dx + d3.event.dy * d3.event.dy;
d.x = d3.event.x;
d.y = d3.event.y;
d3.select(this).attr('transform', 'translate('+[d.x,d.y]+')');
}
function dragended(d) {
if (d._drag.distance < d._drag.threshold) {
d3.select(window).on('click.drag', null);
return;
}
d3.select(this).classed("active", false);
}
.active {
stroke: #000;
stroke-width: 2px;
}
.rect {
pointer-events: all;
stroke: none;
stroke-width: 40px;
}
<script src="//d3js.org/d3.v4.min.js"></script>