Develop Reference

Using d3 curvestep for a hierarchial structure

I am trying to build something similar to a hierachial structure using D3 and i am fairly new to this. This answer is what i am referring to accomplish it.
I referred the following links to get the links/connectors in this particular fashion
Using d3 curveStep
Using d3 linkVertical (linkRadial)
I keep getting the following error multiple times in developer console:
Error: <path> attribute d: Expected moveto path command ('M' or 'm'), "function line
Probably some error in my link function.
Following code is what i am using
var treeData =
{
"name": "Top Level",
"children": [
{
"name": "Level 2: A",
"children": [
{ "name": "Son of A" },
{ "name": "Daughter of A" }
]
},
{ "name": "Level 2: B" }
]
};
// 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" : "black";
})
.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(source.x0, d.y, d)
});
// 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)
return diagonal(d.x, d.parent.y)
});
// Remove any exiting links
var linkExit = link.exit().transition()
.duration(duration)
.attr('d', function(d) {
var o = {x: source.x, y: source.y}
return diagonal(o, o)
})
.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) {
var 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
}*/
function diagonal(s, d) {
var link = d3.line()
.x((x) => xScale(x))
.y((y) => yScale(y))
.curve(d3.curveStep);
return link;
}
// 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);
}
}
<style>
.node circle {
fill: #fff;
stroke: steelblue;
stroke-width: 3px;
}
.node text {
font: 12px sans-serif;
}
.link {
fill: none;
stroke: #ccc;
stroke-width: 2px;
}
</style>
<script src="https://d3js.org/d3.v4.min.js"></script>
I have commented existing diagonal function and tried to introduce curveStep of D3. I have also tweaked a few things related to how the inputs are being passed to the diagonal function.

The issue you have is that d3.line accepts an array of points. You don't end up passing an array to d3.line anywhere.
Your diagonal function should look something like:
function diagonal(array) {
let line = d3.line()
.x(function(d) { return d.y; })
.y(function(d) { return d.x; }) // inverted x/y as you have a horizontal tree
.curve(d3.curveStep);
return line(array);
}
Normally, each link datum is an object, with properties for source and target, we need to pass an array containing both source and target to the diagonal function:
.attr("d", function(d) {
return diagonal([d.source,d.target])
})
Or an equivalent array.
As you've used nodes themselves as the link data, we can still use the same principle with:
.attr("d", function(d) {
return diagonal([d,d.parent])
})
Or, construct an array with objects that have x/y properties. In your case we'll need to construct some objects to represent points for the line generator as you're storing old positioning data we need to access:
Eg:
var treeData =
{
"name": "Top Level",
"children": [
{
"name": "Level 2: A",
"children": [
{ "name": "Son of A" },
{ "name": "Daughter of A" }
]
},
{ "name": "Level 2: B" }
]
};
// 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" : "black";
})
.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([{x: d.parent.x0, y: d.parent.y0 },{x: d.parent.x0, y: d.parent.y0 }])
});
// 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)
return diagonal([{x:d.parent.x, y: d.parent.y}, d]) // changes here
});
// Remove any exiting links
var linkExit = link.exit().transition()
.duration(duration)
.attr('d', function(d) {
var o = {x: source.x, y: source.y}
return diagonal([o,o]) // changes here
})
.remove();
// Store the old positions for transition.
nodes.forEach(function(d){
d.x0 = d.x;
d.y0 = d.y;
});
// changes to diagonal function:
function diagonal(array) {
var link = d3.line()
.x((d) => d.y)
.y((d) => d.x)
.curve(d3.curveStep);
return link(array);
}
// 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);
}
}
<style>
.node circle {
fill: #fff;
stroke: steelblue;
stroke-width: 3px;
}
.node text {
font: 12px sans-serif;
}
.link {
fill: none;
stroke: #ccc;
stroke-width: 2px;
}
</style>
<script src="https://d3js.org/d3.v4.min.js"></script>

Add two possible paths with "window.location.href " under the same condition

I created an interactive tree diagram using the library d3.js and I'm now trying to add the functionality that whenever you click on a node, it redirects you to the page of this element (corresponding to a node).
Previously, I only had elements of type "product" and used this function:
function clack(d) {
if (d.name != "Product Catalog"){
window.location.href = "http://1XX.XX.1.XX/App/redirect?entity_type=product&field_name=itemId&field_value=" + d.id;
}
}
And it worked perfectly!
HOWEVER, I now added another type of elements called "risk_coverages" that are the children of the products, but want to be redirected to the path of those two elements.
In fact, the function for my new entity type "risk_coverages" only would be:
function clack(d) {
if (d.name != "Product Catalog"){
window.location.href = "http://1XX.XX.1.XX/App/redirect?entity_type=risk_coverages&field_name=itemId&field_value=" + d.id;
}
}
My problem is that I don't know how to make the condition for:
IF "entity_type=product&field_name=itemId&field_value=" + d.id , THEN redirect me to my product page
OR
IF "entity_type=risk_coverages&field_name=itemId&field_value=" + d.id , THEN redirect me to my risk coverage page
In English, it would be:
IF it's a product, then look for this product and display its page
OR
IF it's a risk coverage, then look for this risk coverage and display its page
I hope I was clear enough.
Any help would be greatly appreciated!!
Thanks a lot,
Allan
Here is the full code:
<style>
.node, .clickable {
cursor: pointer;
}
.node circle {
fill: #fff;
stroke: steelblue;
stroke-width: 1.5px;
}
.node text:hover {
text-decoration: underline;
}
.node text {
font: 100% sans-serif;
}
.link {
fill: none;
stroke: #ccc;
stroke-width: 1.5px;
}
</style>
Click on a node to expand the tree. Click on a product name to navigate to the product's detail page.
<tree>
<script src="http://d3js.org/d3.v3.min.js"></script>
<script>
var margin = {top: 20, right: 140, bottom: 20, left: 120},
width = 2200 - margin.right - margin.left,
height = 1000 - margin.top - margin.bottom;
var i = 0,
duration = 750,
root;
var tree = d3.layout.tree()
.size([height, width]);
var diagonal = d3.svg.diagonal()
.projection(function(d) { return [d.y, d.x]; });
var svg = d3.select("tree").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 + ")");
d3.json("/App/assets/tree.json", function(error, flare) {
root = flare;
root.x0 = height / 2;
root.y0 = 0;
function collapse(d) {
if (d.children) {
d._children = d.children;
d._children.forEach(collapse);
d.children = null;
}
}
root.children.forEach(collapse);
update(root);
});
d3.select(self.frameElement).style("height", "800px");
function update(source) {
// Compute the new tree layout.
var nodes = tree.nodes(root).reverse(),
links = tree.links(nodes);
// Normalize for fixed-depth.
nodes.forEach(function(d) { d.y = d.depth * 250; });
// Update the nodes…
var node = svg.selectAll("g.node")
.data(nodes, function(d) { return d.id || (d.id = ++i); });
// Enter any new nodes 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 + ")"; })
;
nodeEnter.append("circle")
.attr("r", 1e-6)
.style("fill", function(d) { return d._children ? "lightsteelblue" : "#fff"; })
.on("click", click)
;
nodeEnter.append("text")
.attr("x", function(d) { return d.children || d._children ? -10 : 10; })
.attr("dy", ".35em")
.attr("text-anchor", function(d) { return d.children || d._children ? "end" : "start"; })
.text(function(d) { return d.name; })
.style("fill-opacity", 1e-6)
.attr("class", "hyper").on("click", clack);
// Transition nodes to their new position.
var nodeUpdate = node.transition()
.duration(duration)
.attr("transform", function(d) { return "translate(" + d.y + "," + d.x + ")"; });
nodeUpdate.select("circle")
.attr("r", 4.5)
.style("fill", function(d) { return d._children ? "lightsteelblue" : "#fff"; });
nodeUpdate.select("text")
.style("fill-opacity", 1);
// Transition exiting nodes to the parent's new position.
var nodeExit = node.exit().transition()
.duration(duration)
.attr("transform", function(d) { return "translate(" + source.y + "," + source.x + ")"; })
.remove();
nodeExit.select("circle")
.attr("r", 1e-6);
nodeExit.select("text")
.style("fill-opacity", 1e-6);
// Update the links…
var link = svg.selectAll("path.link")
.data(links, function(d) { return d.target.id; });
// Enter any new links at the parent's previous position.
link.enter().insert("path", "g")
.attr("class", "link")
.attr("d", function(d) {
var o = {x: source.x0, y: source.y0};
return diagonal({source: o, target: o});
});
// Transition links to their new position.
link.transition()
.duration(duration)
.attr("d", diagonal);
// Transition exiting nodes to the parent's new position.
link.exit().transition()
.duration(duration)
.attr("d", function(d) {
var o = {x: source.x, y: source.y};
return diagonal({source: o, target: o});
})
.remove();
// Stash the old positions for transition.
nodes.forEach(function(d) {
d.x0 = d.x;
d.y0 = d.y;
});
}
//collapse function
function collapse(d) {
if (d.children) {
d._children = d.children;
d._children.forEach(collapse);
d.children = null;
}
}
// 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;
}
if (d.parent) {
//console.log(d.parent.children);
//collapse(d.parent.children[0]);
d.parent.children.forEach(function(element) {
if (d !== element) {
collapse(element);
}
});
}
update(d);
}
function clack(d) {
if (d.name != "Product Catalog"){
window.location.href = "http://1XX.XX.1X.XX/App/redirect?entity_type=risk_coverages&field_name=itemId&field_value=" + d.id;
}
}
</script>
`

Script does not work locally but does on server

I am just starting out with javascript and well, I am stuck and it's quite embarrassing too.
First I tried to load a local json file which would not work. I found out about that quite fast.
But when I fixed this mistake it's still not working.
What I do have is basically a copy of http://bl.ocks.org/mbostock/4339083 which works in my browser, while my attempt does not.
Now I have two files:
data.js
var json =
{
"name":"flare",
"children":
[
...
This is so I have my json ready without the need of a webserver
And I have an html file with the script:
<!DOCTYPE html>
<meta charset="utf-8">
<style>
.node {
cursor: pointer;
}
.node circle {
fill: #fff;
stroke: steelblue;
stroke-width: 1.5px;
}
.node text {
font: 10px sans-serif;
}
.link {
fill: none;
stroke: #ccc;
stroke-width: 1.5px;
}
</style>
<body>
<script src="https://d3js.org/d3.v4.min.js"></script>
<script src="data.js"></script>
<script>
alert("here");
var margin = {top: 20, right: 120, bottom: 20, left: 120},
width = 960 - margin.right - margin.left,
height = 800 - margin.top - margin.bottom;
var i = 0,
duration = 750,
root;
var tree = d3.layout.tree()
.size([height, width]);
var diagonal = d3.svg.diagonal()
.projection(function(d) { return [d.y, d.x]; });
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 + ")");
alert("there");
d3.json(json, function(error, flare) {
if (error) throw error;
root = flare;
root.x0 = height / 2;
root.y0 = 0;
function collapse(d) {
if (d.children) {
d._children = d.children;
d._children.forEach(collapse);
d.children = null;
}
}
root.children.forEach(collapse);
update(root);
});
d3.select(self.frameElement).style("height", "800px");
function update(source) {
// Compute the new tree layout.
var nodes = tree.nodes(root).reverse(),
links = tree.links(nodes);
// Normalize for fixed-depth.
nodes.forEach(function(d) { d.y = d.depth * 180; });
// Update the nodes…
var node = svg.selectAll("g.node")
.data(nodes, function(d) { return d.id || (d.id = ++i); });
// Enter any new nodes 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);
nodeEnter.append("circle")
.attr("r", 1e-6)
.style("fill", function(d) { return d._children ? "lightsteelblue" : "#fff"; });
nodeEnter.append("text")
.attr("x", function(d) { return d.children || d._children ? -10 : 10; })
.attr("dy", ".35em")
.attr("text-anchor", function(d) { return d.children || d._children ? "end" : "start"; })
.text(function(d) { return d.name; })
.style("fill-opacity", 1e-6);
// Transition nodes to their new position.
var nodeUpdate = node.transition()
.duration(duration)
.attr("transform", function(d) { return "translate(" + d.y + "," + d.x + ")"; });
nodeUpdate.select("circle")
.attr("r", 4.5)
.style("fill", function(d) { return d._children ? "lightsteelblue" : "#fff"; });
nodeUpdate.select("text")
.style("fill-opacity", 1);
// Transition exiting nodes to the parent's new position.
var nodeExit = node.exit().transition()
.duration(duration)
.attr("transform", function(d) { return "translate(" + source.y + "," + source.x + ")"; })
.remove();
nodeExit.select("circle")
.attr("r", 1e-6);
nodeExit.select("text")
.style("fill-opacity", 1e-6);
// Update the links…
var link = svg.selectAll("path.link")
.data(links, function(d) { return d.target.id; });
// Enter any new links at the parent's previous position.
link.enter().insert("path", "g")
.attr("class", "link")
.attr("d", function(d) {
var o = {x: source.x0, y: source.y0};
return diagonal({source: o, target: o});
});
// Transition links to their new position.
link.transition()
.duration(duration)
.attr("d", diagonal);
// Transition exiting nodes to the parent's new position.
link.exit().transition()
.duration(duration)
.attr("d", function(d) {
var o = {x: source.x, y: source.y};
return diagonal({source: o, target: o});
})
.remove();
// Stash the old positions for transition.
nodes.forEach(function(d) {
d.x0 = d.x;
d.y0 = d.y;
});
}
// 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);
}
</script>
as you can see it's now basically a 1:1 copy.
When I open that .html file though, my page stays blank.
How can this be? I understand that this would happen if I'd try to load a local .json file via the d3.json as that would try doing a http request, which would fail without a webserver to handle it.
But now that the json data is saved in a variable this behaviour makes no sense to me.
Please enlighten me! I'm trying to figure this out for a while now.

Replace this:
d3.json(json, function(error, flare) {
if (error) throw error;
root = flare;
root.x0 = height / 2;
root.y0 = 0;
function collapse(d) {
if (d.children) {
d._children = d.children;
d._children.forEach(collapse);
d.children = null;
}
}
root.children.forEach(collapse);
update(root);
});
with this:
var flare = json;
root = flare;
root.x0 = height / 2;
root.y0 = 0;
function collapse(d) {
if (d.children) {
d._children = d.children;
d._children.forEach(collapse);
d.children = null;
}
}
root.children.forEach(collapse);
update(root);

d3.json(url[, callback]) creates a request for the JSON file at the specified URL with the default mime type application/json. In your code you pass the JSON object instead of a URL. Please try this:
d3.json(json, function(error, flare)
and assign json from data.json to root:
//d3.json(json, function(error, flare) { <-- this will be removed
//if (error) throw error; <-- remove this too not needed !
root = json;
root.x0 = height / 2;
root.y0 = 0;
function collapse(d) {
if (d.children) {
d._children = d.children;
d._children.forEach(collapse);
d.children = null;
}
}
root.children.forEach(collapse);
update(root);
//} <-- don't forget the closing brace.

Auto updating Tree issue

I have the following D3 js similar to
http://mbostock.github.io/d3/talk/20111018/tree.html
I want to have the tree structure auto update based on new json sent by the server.
The new json is sent every 5 seconds.
The issue is that I am not sure how to get rid of the old tree and just leave the updated tree. Currently it just draws a new tree image using d3 js under the most recent tree so very quickly there are tons of tree structures on the page. I would like to know how to remove the old tree image.
Any d3 or JavaScript input?
<style>
.node {
cursor: pointer;
}
.node circle {
fill: #fff;
stroke: steelblue;
stroke-width: 1.5px;
}
.node text {
font: 10px sans-serif;
}
.link {
fill: none;
stroke: #ccc;
stroke-width: 1.5px;
}
</style>
<script src="http://d3js.org/d3.v3.min.js"></script>
<script>
var treeData2 = <%- JSON.stringify(treeJSON) %>;
drawTree();
function drawTree () {
treeData2.name = "broadcaster";
console.log("tree data = ", treeData2);
var margin = {top: 20, right: 120, bottom: 20, left: 120},
width = 960 - margin.right - margin.left,
height = 800 - margin.top - margin.bottom;
var i = 0,
duration = 750,
root;
var tree = d3.layout.tree()
.size([height, width]);
var diagonal = d3.svg.diagonal()
.projection(function(d) { return [d.y, d.x]; });
svg = d3.select("body").append("svg")
.style("overflow", "scroll")
.attr("width", width + margin.right + margin.left)
.attr("height", height + margin.top + margin.bottom)
.append("g")
.append("svg:g")
.attr("class","drawarea")
.attr("transform", "translate(" + margin.left + "," + margin.top + ")");
root = treeData2;
root.x0 = height / 2;
root.y0 = 0;
function collapse(d) {
if (d.children) {
d._children = d.children;
d._children.forEach(collapse);
d.children = null;
}
}
root.children.forEach(collapse);
update(root);
var inter = setInterval(function() {
socket.get('/channel/13/tree', function(updatedJSON) {
console.log("Updated Json = ", updatedJSON);
treeData2 = updatedJSON;
})
drawTree();
}, 5000);
d3.select(self.frameElement).style("height", "800px");
function update(source) {
// Compute the new tree layout.
var nodes = tree.nodes(root).reverse(),
links = tree.links(nodes);
// Normalize for fixed-depth.
nodes.forEach(function(d) { d.y = d.depth * 180; });
// Update the nodes…
var node = svg.selectAll("g.node")
.data(nodes, function(d) { return d.id || (d.id = ++i); });
// Enter any new nodes 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);
nodeEnter.append("circle")
.attr("r", 1e-6)
.style("fill", function(d) { return d._children ? "lightsteelblue" : "#fff"; });
nodeEnter.append("text")
.attr("x", function(d) { return d.children || d._children ? -10 : 10; })
.attr("dy", ".35em")
.attr("text-anchor", function(d) { return d.children || d._children ? "end" : "start"; })
.text(function(d) { return d.name; })
.style("fill-opacity", 1e-6);
// Transition nodes to their new position.
var nodeUpdate = node.transition()
.duration(duration)
.attr("transform", function(d) { return "translate(" + d.y + "," + d.x + ")"; });
nodeUpdate.select("circle")
.attr("r", 4.5)
.style("fill", function(d) { return d._children ? "lightsteelblue" : "#fff"; });
nodeUpdate.select("text")
.style("fill-opacity", 1);
// Transition exiting nodes to the parent's new position.
var nodeExit = node.exit().transition()
.duration(duration)
.attr("transform", function(d) { return "translate(" + source.y + "," + source.x + ")"; })
.remove();
nodeExit.select("circle")
.attr("r", 1e-6);
nodeExit.select("text")
.style("fill-opacity", 1e-6);
// Update the links…
var link = svg.selectAll("path.link")
.data(links, function(d) { return d.target.id; });
// Enter any new links at the parent's previous position.
link.enter().insert("path", "g")
.attr("class", "link")
.attr("d", function(d) {
var o = {x: source.x0, y: source.y0};
return diagonal({source: o, target: o});
});
// Transition links to their new position.
link.transition()
.duration(duration)
.attr("d", diagonal);
// Transition exiting nodes to the parent's new position.
link.exit().transition()
.duration(duration)
.attr("d", function(d) {
var o = {x: source.x, y: source.y};
return diagonal({source: o, target: o});
})
.remove();
// Stash the old positions for transition.
nodes.forEach(function(d) {
d.x0 = d.x;
d.y0 = d.y;
});
d3.select("svg")
.call(d3.behavior.zoom()
.scaleExtent([0.5, 5])
.on("zoom", zoom));
node
.exit()
.remove();
link
.exit()
.remove();
}
// 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);
}
// Allows for zoom and drag properties
function zoom() {
var scale = d3.event.scale,
translation = d3.event.translate,
tbound = -height * scale,
bbound = height * scale,
lbound = (-width + margin.right) * scale,
rbound = (width- margin.left) * scale;
// limit translation to thresholds
translation = [
Math.max(Math.min(translation[0], rbound), lbound),
Math.max(Math.min(translation[1], bbound), tbound)
];
d3.select(".drawarea")
.attr("transform", "translate(" + translation + ")" +
" scale(" + scale + ")");
}
}
</script>

To delete the old SVG, simply select and remove it:
d3.selectAll("svg").remove();

Color paths in d3.layout.tree

I want to color paths in my collapsible d3 layout based on one the node directly above the lowest level. Obviously there will only be different colors when more then one of the nodes directly above the child node is expanded.
I am using the code from the d3js example with only minor modifications:
function buildTree(data) {
var margin = {top: 20, right: 120, bottom: 20, left: 120},
width = 960 - margin.right - margin.left,
height = 800 - margin.top - margin.bottom;
var i = 0,
duration = 750,
root;
var tree = d3.layout.tree()
.size([height, width]);
var diagonal = d3.svg.diagonal()
.projection(function (d) {
return [d.y, d.x];
});
var svg = d3.select("#node").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 + ")");
root = data;
root.x0 = height / 2;
root.y0 = 0;
function collapse(d) {
if (d.children) {
d._children = d.children;
d._children.forEach(collapse);
d.children = null;
}
}
root.children.forEach(collapse);
update(root);
d3.select(self.frameElement).style("height", "800px");
function update(source) {
// Compute the new tree layout.
var nodes = tree.nodes(root).reverse(),
links = tree.links(nodes);
// Normalize for fixed-depth.
nodes.forEach(function (d) {
d.y = d.depth * 180;
});
// Update the nodes…
var node = svg.selectAll("g.node")
.data(nodes, function (d) {
return d.id || (d.id = ++i);
});
// Enter any new nodes 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);
nodeEnter.append("circle")
.attr("r", 1e-6)
.style("fill", function (d) {
return d._children ? "lightsteelblue" : "#fff";
});
nodeEnter.append("text")
.attr("x", function (d) {
return d.children || d._children ? -10 : 10;
})
.attr("dy", "1em")
.attr("text-anchor", function (d) {
return d.children || d._children ? "end" : "start";
})
.text(function (d) {
return d.name;
})
.style("fill-opacity", 1e-6);
// Transition nodes to their new position.
var nodeUpdate = node.transition()
.duration(duration)
.attr("transform", function (d) {
return "translate(" + d.y + "," + d.x + ")";
});
nodeUpdate.select("circle")
.attr("r", 4.5)
.style("fill", function (d) {
return d._children ? "lightsteelblue" : "#fff";
});
nodeUpdate.select("text")
.style("fill-opacity", 1);
// Transition exiting nodes to the parent's new position.
var nodeExit = node.exit().transition()
.duration(duration)
.attr("transform", function (d) {
return "translate(" + source.y + "," + source.x + ")";
})
.remove();
nodeExit.select("circle")
.attr("r", 1e-4);
nodeExit.select("text")
.style("fill-opacity", 1e-6);
// Update the links…
var link = svg.selectAll("path.link")
.data(links, function (d) {
return d.target.id;
});
// Enter any new links at the parent's previous position.
link.enter().insert("path", "g")
.attr("class", "link")
.attr("d", function (d) {
var o = {x: source.x0, y: source.y0};
return diagonal({source: o, target: o});
});
// Transition links to their new position.
link.transition()
.duration(duration)
.attr("d", diagonal);
// Transition exiting nodes to the parent's new position.
link.exit().transition()
.duration(duration)
.attr("d", function (d) {
var o = {x: source.x, y: source.y};
return diagonal({source: o, target: o});
})
.remove();
// Stash the old positions for transition.
nodes.forEach(function (d) {
d.x0 = d.x;
d.y0 = d.y;
});
}
// 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);
}
}
The "link" colors (which is what I want to change) are coming from some defined styles:
.node {
cursor: pointer;
}
.node circle {
fill: #fff;
stroke: steelblue;
stroke-width: 2px;
}
.node text {
font: 12px sans-serif;
fill: white;
}
.link {
fill: none;
stroke: white;
stroke-width: 1.5px;
}
I am on a black background so I would like to keep the colors to red, green, blue, white, etc (those that can be seen against black).

You can color the links dynamically by setting the stroke color in the code. The depth of a node (which, if I'm understanding correctly is what you're after) is part of its data so you can reference it directly.
var color = d3.scale.category20();
// ...
link.transition()
.duration(duration)
.attr("d", diagonal)
.style("stroke", function(d) { return color(d.source.depth); });

You can set the link colors when they are getting created, here in the code:
link.enter().insert("path", "g")
.attr("class", "link")
.attr("d", function (d) {
var o = {x: source.x0, y: source.y0};
return diagonal({source: o, target: o});
})
.attr("stroke", function (d) { return 'blue'; })
// ^^ return your color here.
And you can then safely remove the CSS definition for the stroke of .link.