d3js Moving the labels next to the nodes - d3.js

Question

I am developing a project on pattern representation through graphs. I have come to retrieve the data from a json to generate the graphs and locate the labels associated with the nodes (I would also like to locate the labels corresponding to the links). However, when moving the nodes, I am unable to move the labels. Any help? See the code here:
var width = 960,
height = 500,
resolution = 150,
r = 15;
var graph = {
"nodes": [
{"task": "1", "label": "1", "social": "I", "id": 1, "x": 150, "y": 450},
{"task": "2", "label": "2", "social": "G", "id": 2, "x": 300, "y": 150},
{"task": "3", "label": "3", "social": "T", "id": 3, "x": 450, "y": 300}
],
"links": [
{"source": "1", "target": "2", "type": "N:1"},
{"source": "2", "target": "3", "type": "1:N"},
{"source": "1", "target": "3", "type": "1:1"}
]
}
var margin = {
top: -5,
right: -5,
bottom: -5,
left: -5
};
var colors = d3.scale.category20();
var svg = d3.select('body').append('svg')
.attr('width', width)
.attr('height', height);
var force = d3.layout.force()
.charge(-200)
.linkDistance(50)
.size([width + margin.left + margin.right, height + margin.top + margin.bottom])
.nodes(graph.nodes);
var drag = d3.behavior.drag()
.origin(function(d) { return d; })
.on('drag', dragged);
svg.selectAll('.vertical')
.data(d3.range(1, width / resolution))
.enter().append('line')
.attr('class', 'vertical')
.attr('x1', function(d) { return d * resolution; })
.attr('y1', 0)
.attr('x2', function(d) { return d * resolution; })
.attr('y2', height);
svg.selectAll('.horizontal')
.data(d3.range(1, height / resolution))
.enter().append('line')
.attr('class', 'horizontal')
.attr('x1', 0)
.attr('y1', function(d) { return d * resolution; })
.attr('x2', width)
.attr('y2', function(d) { return d * resolution; });
svg.append('defs').append('marker')
.attr({'id':'arrowhead',
'viewBox':'-0 -5 10 10',
'refX':25,
'refY':0,
'orient':'auto',
'markerWidth':5,
'markerHeight':5,
'xoverflow':'visible'})
.append('svg:path')
.attr('d', 'M 0,-5 L 10 ,0 L 0,5')
.attr('fill', '#777')
.style('stroke','none');
var link = svg.selectAll("svg.link")
.data(graph.links)
.enter().append("line")
.attr("class", "link")
.attr('marker-end','url(#arrowhead)')
.attr("data-source", function (d) {
return d.source;
})
.attr("data-target", function (d) {
return d.target;
})
.attr("x1", function (d) {
for (let node of graph.nodes) {
if (node.task === d.source)
return node.x;
}
})
.attr("x2", function (d) {
for (let node of graph.nodes) {
if (node.task === d.target)
return node.x;
}
})
.attr("y1", function (d) {
for (let node of graph.nodes) {
if (node.task === d.source)
return node.y;
}
})
.attr("y2", function (d) {
for (let node of graph.nodes) {
if (node.task === d.target)
return node.y;
}
})
.style("stroke-width", function(d) {
return Math.sqrt(d.value);
});
var node = svg.selectAll("svg.node")
.data(graph.nodes)
.enter().append('g');
node.append("circle")
.attr("class", "node")
.attr('cx', function(d) { return d.x; })
.attr('cy', function(d) { return d.y; })
.attr('r', r)
.call(drag);//
//text element
node.append("title")
.text(function (d) {return d.social});
node.append("text")
//.attr("dx", )
//.attr("dy", 6)
.attr("class", "font")
.attr('dx', function(d) { return d.x-6; })
.attr('dy', function(d) { return d.y+6; })
.text(function(d) { return d.social; });
force.on("tick", function () {
link.attr("x1", function (d) { return d.source.x; })
.attr("y1", function (d) { return d.source.y; })
.attr("x2", function (d) { return d.target.x; })
.attr("y2", function (d) { return d.target.y; });
node.attr("transform", function(d) { return "translate(" + d.x + "," + d.y + ")"; });
});
function dragged(d) {
var x = d3.event.x,
y = d3.event.y,
gridX = round(Math.max(r, Math.min(width - r, x)), resolution),
gridY = round(Math.max(r, Math.min(height - r, y)), resolution);
d3.select(this).attr('cx', d.x = gridX).attr('cy', d.y = gridY);
d3.select(this).attr('dx', d.x = gridX).attr('dy', d.y = gridY);
d3.selectAll(`[data-source='${d.task}']`).attr('x1', d.x).attr('y1', d.y);
d3.selectAll(`[data-target='${d.task}']`).attr('x2', d.x).attr('y2', d.y);
}
function round(p, n) {
return p % n < n / 2 ? p - (p % n) : p + n - (p % n);
}
.node {
fill:#ccc;
stroke: #fff;
stroke-width: 2px;
}
.node-active {
stroke: #555;
stroke-width: 1.5px;
}
link-active {
stroke: #555;
stroke-opacity: 5;
}
line {
stroke: rgb(212, 212, 212);
stroke-width: 1px;
shape-rendering: crispEdges;
}
.overlay {
fill: none;
pointer-events: all;
}
.link{
stroke: #ccc;
stroke-width: 2px;
}
svg {
box-sizing: border-box;
border: 1px solid rgb(212, 212, 212);
}
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<title>[D3]</title>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="robots" content="noindex, nofollow">
<meta name="googlebot" content="noindex, nofollow">
<meta name="viewport" content="width=device-width, initial-scale=1">
<body>
<script src="https://d3js.org/d3.v3.min.js" charset="utf-8"></script>
</body>

Answer 1

Add an identification attribute to <circle> and <text> elements:
...attr('node-id', d => d.social)
Move the text along with the circle:
d3.select(`text[node-id='${d.social}']`).attr('dx', d.x).attr('dy', d.y)
Use text-anchor and alignment-baseline for <text> labels instead of offsets (+6/-6):
...attr('text-anchor', 'middle')
.attr('alignment-baseline', 'middle')
.attr('dx', function(d) { return d.x; })
.attr('dy', function(d) { return d.y; })
I also enlarged the <circle>s to make them easy to drag...
var width = 960,
height = 500,
resolution = 150,
r = 15;
var graph = {
"nodes": [
{"task": "1", "label": "1", "social": "I", "id": 1, "x": 150, "y": 450},
{"task": "2", "label": "2", "social": "G", "id": 2, "x": 300, "y": 150},
{"task": "3", "label": "3", "social": "T", "id": 3, "x": 450, "y": 300}
],
"links": [
{"source": "1", "target": "2", "type": "N:1"},
{"source": "2", "target": "3", "type": "1:N"},
{"source": "1", "target": "3", "type": "1:1"}
]
}
var margin = {
top: -5,
right: -5,
bottom: -5,
left: -5
};
var colors = d3.scale.category20();
var svg = d3.select('body').append('svg')
.attr('width', width)
.attr('height', height);
var force = d3.layout.force()
.charge(-200)
.linkDistance(50)
.size([width + margin.left + margin.right, height + margin.top + margin.bottom])
.nodes(graph.nodes);
var drag = d3.behavior.drag()
.origin(function(d) { return d; })
.on('drag', dragged);
svg.selectAll('.vertical')
.data(d3.range(1, width / resolution))
.enter().append('line')
.attr('class', 'vertical')
.attr('x1', function(d) { return d * resolution; })
.attr('y1', 0)
.attr('x2', function(d) { return d * resolution; })
.attr('y2', height);
svg.selectAll('.horizontal')
.data(d3.range(1, height / resolution))
.enter().append('line')
.attr('class', 'horizontal')
.attr('x1', 0)
.attr('y1', function(d) { return d * resolution; })
.attr('x2', width)
.attr('y2', function(d) { return d * resolution; });
svg.append('defs').append('marker')
.attr({'id':'arrowhead',
'viewBox':'-0 -5 10 10',
'refX':40,
'refY':0,
'orient':'auto',
'markerWidth':5,
'markerHeight':5,
'xoverflow':'visible'})
.append('svg:path')
.attr('d', 'M 0,-5 L 10 ,0 L 0,5')
.attr('fill', '#777')
.style('stroke','none');
var link = svg.selectAll("svg.link")
.data(graph.links)
.enter().append("line")
.attr("class", "link")
.attr('marker-end','url(#arrowhead)')
.attr("data-source", function (d) {
return d.source;
})
.attr("data-target", function (d) {
return d.target;
})
.attr("x1", function (d) {
for (let node of graph.nodes) {
if (node.task === d.source)
return node.x;
}
})
.attr("x2", function (d) {
for (let node of graph.nodes) {
if (node.task === d.target)
return node.x;
}
})
.attr("y1", function (d) {
for (let node of graph.nodes) {
if (node.task === d.source)
return node.y;
}
})
.attr("y2", function (d) {
for (let node of graph.nodes) {
if (node.task === d.target)
return node.y;
}
})
.style("stroke-width", function(d) {
return Math.sqrt(d.value);
});
var node = svg.selectAll("svg.node")
.data(graph.nodes)
.enter().append('g');
node.append("circle")
.attr("class", "node")
.attr('node-id', d => d.social)
.attr('cx', function(d) { return d.x; })
.attr('cy', function(d) { return d.y; })
.attr('r', r * 2)
.call(drag);//
node.append("text")
.attr("class", "label")
.attr('node-id', d => d.social)
.attr('text-anchor', 'middle')
.attr('alignment-baseline', 'middle')
.attr('dx', function(d) { return d.x; })
.attr('dy', function(d) { return d.y; })
.text(function(d) { return d.social; });
force.on("tick", function () {
link.attr("x1", function (d) { return d.source.x; })
.attr("y1", function (d) { return d.source.y; })
.attr("x2", function (d) { return d.target.x; })
.attr("y2", function (d) { return d.target.y; });
node.attr("transform", function(d) { return "translate(" + d.x + "," + d.y + ")"; });
});
function dragged(d) {
var x = d3.event.x,
y = d3.event.y,
gridX = round(Math.max(r, Math.min(width - r, x)), resolution),
gridY = round(Math.max(r, Math.min(height - r, y)), resolution);
d3.select(this).attr('cx', d.x = gridX).attr('cy', d.y = gridY);
d3.select(this).attr('dx', d.x = gridX).attr('dy', d.y = gridY);
d3.selectAll(`[data-source='${d.task}']`).attr('x1', d.x).attr('y1', d.y);
d3.selectAll(`[data-target='${d.task}']`).attr('x2', d.x).attr('y2', d.y);
d3.select(`text[node-id='${d.social}']`).attr('dx', d.x).attr('dy', d.y)
}
function round(p, n) {
return p % n < n / 2 ? p - (p % n) : p + n - (p % n);
}
.node {
fill:#ccc;
stroke: #fff;
stroke-width: 2px;
}
.node-active {
stroke: #555;
stroke-width: 1.5px;
}
link-active {
stroke: #555;
stroke-opacity: 5;
}
line {
stroke: rgb(212, 212, 212);
stroke-width: 1px;
shape-rendering: crispEdges;
}
.overlay {
fill: none;
pointer-events: all;
}
.link{
stroke: #ccc;
stroke-width: 2px;
}
svg {
box-sizing: border-box;
border: 1px solid rgb(212, 212, 212);
}
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<title>[D3]</title>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<meta name="robots" content="noindex, nofollow">
<meta name="googlebot" content="noindex, nofollow">
<meta name="viewport" content="width=device-width, initial-scale=1">
<body>
<script src="https://d3js.org/d3.v3.min.js" charset="utf-8"></script>
</body>