Add DOM-style hierarchy traversal methods?

[albell]

I am working with some large-ish hierarchies, with over 10,000 nodes, and a bit of custom data. Too large to be in the DOM all at once, so they need to be queried. I am finding that I often need to be able to traverse a hierarchy, starting from a given node, looking for a node that satisfies some condition. This is straightforward to do manually, but in results in a lot of for loops, which aren't really in the D3 idiom. The existing each-* methods have the slight performance disadvantage that there is no way early-exit the loop once the target node has been found. It might be nice to have that option as an API refinement.

Another option could be jQuery-esque .closest and .find methods that looked up and down the hierarchy, respectively, and returned the first "matching" node.

Thanks.

[mbostock]

You can extend d3.hierarchy.prototype to define new methods on hierarchy nodes, as noted in the README. You can see the existing method implementations in src/hierarchy. The name node.find(filter) sounds fine for finding the first descendant in breadth-first order (I like the similarity to array.find), but I’d probably use the name node.findAncestor(filter) rather than node.closest since that’s more self-explanatory.

I don’t have any immediate plans to implement new methods, but if you implement something useful, feel free to send a pull request.