D3 Treechart : Text on link(path) in version 4 - d3.js

Question

Problem: highlighted text(in the image below) is been over-written(therefore its looking bold) when the node is expanded.
Expected Output:
Collapsible d3 Treechart
var linktext = svg.selectAll("g.link")
.data(links, function (d) {
console.log("Text Data Id..."+d.id);
return d.id;
});
linktext.enter()
.insert("g")
.merge(linktext)
.attr("class", "link")
.attr("transform", function (d) {
return "translate(" + ((d.parent.y + d.y) / 2) + "," + ((d.parent.x +d.x) / 2) + ")"; })
.append("text")
.attr("dy", ".35em")
.attr("text-anchor", "middle")
.text(function (d) {
debugger;
console.log("Text Data Rule..."+d.data.rule);
return d.data.rule;
});
linktext.exit().transition()
.remove();

Answer 1

Your problem is caused due to .merge function, this code will fix the multiple-element issue
var treeData =
{ "name": "E", "children": [{ "name": "A", "rule": "yes", "children": [{ "name": "B", "rule": "<=3.843750000000001", "children": [{ "name": "C", "rule": "yes" }, { "name": "D", "rule": "no", "children": [{ "name": "Sex", "rule": "yes", "children": [{ "name": "E", "rule": "Male", "children": [{ "name": "F", "rule": "<=62.5125" }, { "name": "G", "rule": ">62.5125", "children": [{ "name": "H", "rule": "yes" }, { "name": "K", "rule": "no" }] }] }, { "name": "I", "rule": "Female" }] }, { "name": "J", "rule": "no" }] }] }, { "name": "K", "rule": ">3.843750000000001", "children": [{ "name": "Q", "rule": "yes" }, { "name": "H", "rule": "no", "children": [{ "name": "S", "rule": "yes" }, { "name": "N", "rule": "no" }] }] }] }, { "name": "L", "rule": "no", "children": [{ "name": "S", "rule": "yes", "children": [{ "name": "T", "rule": "<=82.025", "children": [{ "name": "Y", "rule": "<=102.9125" }, { "name": "Malaise", "rule": ">102.9125", "children": [{ "name": "Age", "rule": "no", "children": [{ "name": "J", "rule": ">40.6625", "children": [{ "name": "M", "rule": "yes", "children": [{ "name": "N", "rule": "no", "children": [{ "name": "G", "rule": "yes" }, { "name": "E", "rule": "no" }] }] }] }] }] }] }] }, { "name": "survive", "rule": "no" }] }] };
// Set the dimensions and margins of the diagram
var margin = { top: 20, right: 90, bottom: 30, left: 90 },
width = 960 - margin.left - margin.right,
height = 500 - margin.top - margin.bottom;
// append the svg object to the body of the page
// appends a 'group' element to 'svg'
// moves the 'group' element to the top left margin
var svg = d3.select("body").append("svg")
.attr("width", width + margin.right + margin.left)
.attr("height", height + margin.top + margin.bottom)
.append("g")
.attr("transform", "translate("
+ margin.left + "," + margin.top + ")");
var i = 0,
duration = 750,
root;
// declares a tree layout and assigns the size
var treemap = d3.tree().size([height, width]);
// Assigns parent, children, height, depth
root = d3.hierarchy(treeData, function (d) { return d.children; });
root.x0 = height / 2;
root.y0 = 0;
// Collapse after the second level
root.children.forEach(collapse);
update(root);
// Collapse the node and all it's children
function collapse(d) {
if (d.children) {
d._children = d.children
d._children.forEach(collapse)
d.children = null
}
}
function update(source) {
// Assigns the x and y position for the nodes
var treeData = treemap(root);
// Compute the new tree layout.
var nodes = treeData.descendants(),
links = treeData.descendants().slice(1);
// Normalize for fixed-depth.
nodes.forEach(function (d) { d.y = d.depth * 180 });
// ****************** Nodes section ***************************
// Update the nodes...
var node = svg.selectAll('g.node')
.data(nodes, function (d) { return d.id || (d.id = ++i); });
// Enter any new modes at the parent's previous position.
var nodeEnter = node.enter().append('g')
.attr('class', 'node')
.attr("transform", function (d) {
return "translate(" + source.y0 + "," + source.x0 + ")";
})
.on('click', click);
// Add Circle for the nodes
nodeEnter.append('circle')
.attr('class', 'node')
.attr('r', 1e-6)
.style("fill", function (d) {
return d._children ? "lightsteelblue" : "#fff";
});
// Add labels for the nodes
nodeEnter.append('text')
.attr("dy", ".35em")
.attr("x", function (d) {
return d.children || d._children ? -13 : 13;
})
.attr("text-anchor", function (d) {
return d.children || d._children ? "end" : "start";
})
.text(function (d) { return d.data.name; });
// UPDATE
var nodeUpdate = nodeEnter.merge(node);
// Transition to the proper position for the node
nodeUpdate.transition()
.duration(duration)
.attr("transform", function (d) {
return "translate(" + d.y + "," + d.x + ")";
});
// Update the node attributes and style
nodeUpdate.select('circle.node')
.attr('r', 10)
.style("fill", function (d) {
return d._children ? "lightsteelblue" : "#fff";
})
.attr('cursor', 'pointer');
// Remove any exiting nodes
var nodeExit = node.exit().transition()
.duration(duration)
.attr("transform", function (d) {
return "translate(" + source.y + "," + source.x + ")";
})
.remove();
// On exit reduce the node circles size to 0
nodeExit.select('circle')
.attr('r', 1e-6);
// On exit reduce the opacity of text labels
nodeExit.select('text')
.style('fill-opacity', 1e-6);
// ****************** links section ***************************
// Update the links...
var link = svg.selectAll('path.link')
.data(links, function (d) { return d.id; });
// Enter any new links at the parent's previous position.
var linkEnter = link.enter().insert('path', "g")
.attr("class", "link")
.attr('d', function (d) {
var o = { x: source.x0, y: source.y0 }
return diagonal(o, o)
});
// UPDATE
var linkUpdate = linkEnter.merge(link);
// Transition back to the parent element position
linkUpdate.transition()
.duration(duration)
.attr('d', function (d) { return diagonal(d, d.parent) });
// Remove any exiting links
link.exit().transition()
.duration(duration)
.attr('d', function (d) {
var o = { x: source.x, y: source.y }
return diagonal(o, o)
})
.remove();
var linktext = svg.selectAll("g.link")
.data(links, function (d) {
return d.id;
});
linktext.enter()
.insert("g")
//.merge(linktext)
.attr("class", "link")
.attr("transform", function (d) {
return "translate(" + ((d.parent.y + d.y) / 2) + "," + ((d.parent.x + d.x) / 2) + ")";
})
.append("text")
.attr("dy", ".35em")
.attr("text-anchor", "middle")
.text(function (d) {
return d.data.rule;
});
linktext.exit().remove();
// Store the old positions for transition.
nodes.forEach(function (d) {
d.x0 = d.x;
d.y0 = d.y;
});
// Creates a curved (diagonal) path from parent to the child nodes
function diagonal(s, d) {
path = `M ${s.y} ${s.x}
C ${(s.y + d.y) / 2} ${s.x},
${(s.y + d.y) / 2} ${d.x},
${d.y} ${d.x}`
return path
}
}
// Toggle children on click.
function click(d) {
if (d.children) {
d._children = d.children;
d.children = null;
} else {
d.children = d._children;
d._children = null;
}
update(d);
}
Also replace your css with the below to fix the link-text font:
.node circle {
fill: #fff;
stroke: steelblue;
stroke-width: 3px;
}
.node text {
font: 12px sans-serif;
}
path.link {
fill: none;
stroke: #000;
stroke-width: 1px;
}