Treemap – how to calculate width & height without x0, x1, etc

Here’s the project description:

Most d3.treemap examples I’ve found seem to have a dataset that already contains x0, x1, y0, and y1 values.
In those examples, the height of a treemap tile is calculated as d.y1 - d.y0 and the width as d.x1 - d.x0.

In the given dataset, however, I only have one numerical value for each node, the value of the Kickstarter pledge.

How do I calculate the height and width of a tile with only the overall pledge value, without those coordinate values?

UPDATE: A console.log on the root var revealed what the coordinate values are:

var root = d3.hierarchy(data)
    .eachBefore(function(d) { = (d.parent ? + "." : "") +; 
    .sort(function(a, b) { return b.height - a.height || b.value - a.value; });
  console.log("the root is: ");