D3.js可折叠树-展开/折叠节点

我在Przemek提示的帮助下获得了解决方案。现在它可以完美运行了。:)

function click(d) {
var index;
for(var i=0;i<d.parent.children.length;i++){//length of current label
    if(d.parent.children[i].name===d.name)
        index = i;
};

for(var i=0;i<d.parent.children.length;i++){
    if(typeof d.parent.children[i].children!=="undefined" && i!=index){//if child is expnd then make null
        d.parent.children[i]._children=d.parent.children[i].children;
        d.parent.children[i].children= null;
    }
}
if (d.children) {
    d._children = d.children;
    d.children = null;
} else {
    d.children = d._children;
    d._children = null;
}
update(d);
}