How can I start with all the nodes collapsed in d3js?

Question

Starting from this example http://bl.ocks.org/1062288 I would like to have a tree with all the nodes collapsed, so the initial graph should contain only one node (the root).

Answer 1

Put this here for future readers:

d3.json("json/results.json", function(json) {
    root = json;
    root.x0 = h / 2;
    root.y0 = 0;
    function toggleAll(d) {
    if (d.children) {
      d.children.forEach(toggleAll);
      toggle(d);
    }
}

root.children.forEach(toggleAll);

toggle(root);
update(root);
});

http://jsfiddle.net/chrisloughnane/vV3Sc/