Removing node and its children from d3js tree layout

Question

I'm beginning with d3js playing around with d3js tree layout. I started with this blo.cks example

I'm trying to remove a path and it's children on clicking a path , following is my current code.

var treeData = [
  {
    "name": "Top Level",
    "parent": "null",
    "children": [
      {
        "name": "Level 2: A",
        "parent": "Top Level",
        "children": [
          {
            "name": "Son of A",
            "parent": "Level 2: A"
          },
          {
            "name": "Daughter of A",
            "parent": "Level 2: A"
          }
        ]
      },
      {
        "name": "Level 2: B",
        "parent": "Top Level"
      }
    ]
  }
];


// ************** Generate the tree diagram	 *****************
var margin = {top: 20, right: 120, bottom: 20, left: 120},
	width = 960 - margin.right - margin.left,
	height = 500 - 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 + ")");

root = treeData[0];
root.x0 = height / 2;
root.y0 = 0;
  
update(root);

d3.select(self.frameElement).style("height", "500px");

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 ? -13 : 13; })
	  .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", 10)
	  .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});
	  })
      .on("click",removeNode); //remove node on click
  
  //function to remove node 
  
  function removeNode()
  {
     this.remove();
  }
  
  

  // 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);
}

	
	.node {
		cursor: pointer;
	}

	.node circle {
	  fill: #fff;
	  stroke: steelblue;
	  stroke-width: 3px;
	}

	.node text {
	  font: 12px sans-serif;
	}

	.link {
	  fill: none;
	  stroke: #ccc;
	  stroke-width: 2px;
	}

Right now on clicking the path , the path is getting removed. I also would like to remove the connected node ( child ) and all it's successors ( if any ) .

How can i access the child nodes inside the click function triggered by the path ?

Cyril Cherian · Accepted Answer

This is wrong:

function removeNode()
  {
     this.remove();//it will remove only the link.
  }

You can do something like this to remove the node and all its children.

function removeNode(d)
{
  //this is the links target node which you want to remove
     var target = d.target;
     //make new set of children
     var children = [];
     //iterate through the children 
     target.parent.children.forEach(function(child){
       if (child.id != target.id){
         //add to the child list if target id is not same 
         //so that the node target is removed.
         children.push(child);
       }
     });
     //set the target parent with new set of children sans the one which is removed
     target.parent.children = children;
     //redraw the parent since one of its children is removed
     update(d.target.parent)
}

working example here

Hope this helps!

Removing node and its children from d3js tree layout

Answers (2)

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