I am working on a force directed graph in D3. I want to highlight the mouseover'd node, its links, and its child nodes by setting all of the other nodes and links to a lower opacity.
In this example, http://jsfiddle.net/xReHA/, I am able to fade out all of the links and nodes then fade in the connected links, but, so far, I haven't been able to elegantly fade in the connected nodes that are children of the currently mouseover'd node.
This is the key function from the code:
function fade(opacity) {
return function(d, i) {
//fade all elements
svg.selectAll("circle, line").style("opacity", opacity);
var associated_links = svg.selectAll("line").filter(function(d) {
return d.source.index == i || d.target.index == i;
}).each(function(dLink, iLink) {
//unfade links and nodes connected to the current node
d3.select(this).style("opacity", 1);
//THE FOLLOWING CAUSES: Uncaught TypeError: Cannot call method 'setProperty' of undefined
d3.select(dLink.source).style("opacity", 1);
d3.select(dLink.target).style("opacity", 1);
});
};
}
I am getting a Uncaught TypeError: Cannot call method 'setProperty' of undefined
error when I try to set the opacity on an element I loaded from the source.target. I suspect this is not the right way to load that node as a d3 object, but I can't find another way to load it without iterating over all of the nodes again to find the ones that match the link's target or source. To keep the performance reasonable, I don't want to iterate over all the nodes more than necessary.
I took the example of fading the links from https://bl.ocks.org/mbostock/4062006:
However, that doesn't show how to alter the connected child nodes.
Any good suggestions on how to solve or improve this will be furiously upvoted :)