partition.padding should accept a function?

[alexlenail]

What if partition.padding accepted a function which returned an int, instead of just an int?

d3.partition().size([w, h]).padding(d => d.height * 10).round(true);

Result would look like:

[alexlenail]

I have solved this problem via this ghastly code:

let sum_counts_objects = (a, b) => _.object(_.uniq(Object.keys(a).concat(Object.keys(b))).map(key => [key, (a[key] || 0) + (b[key] || 0)]));

...

margin = {'2': 10};

...


    function offset(partition, margin) {

        counter = 0; current_depth = 0;
        partition.each((node) => {
            node.num_below = _(node.descendants().map(d => d.height)).countBy();

            if (node.depth !== current_depth) { current_depth = node.depth; counter = 0; }
            node.sibling_index = counter; counter += 1;
        });

        partition.each((node) => {
            if (node.parent) {
                node.num_left = node.parent.children.filter(sibling => sibling.sibling_index !== undefined && sibling.sibling_index < node.sibling_index)
                                                    .reduce((acc, sibling) => sum_counts_objects(acc, sibling.num_below), {});

                node.offset = d3.sum(Object.entries(node.num_left).map(([level, num]) => (margin[level] || 0)*(num))) + node.parent.offset;
                node.x0 += node.offset;
                node.x1 += node.offset + d3.sum(Object.entries(node.num_below).map(([level, num]) => (margin[level] || 0)*(num-1)));
            } else {
                node.offset = 0;
                node.num_left = 0;
                node.x1 += d3.sum(Object.entries(node.num_below).map(([level, num]) => (margin[level] || 0)*(num-1)));
            }
        });

    }

I believe this is a fairly general approach, if you'd like to specify the margin between items at each of the levels, vial the margin object.