D3.js Tree Expand All and Collapse All

Question

I\'m building a Tree using D3.js and what I am trying to do is add two buttons, Expand All and Collapse All to the top of the page like this.

Answer 1

Try this code. Here is the working JsFiddle.

function expand(d){   
    var children = (d.children)?d.children:d._children;
    if (d._children) {        
        d.children = d._children;
        d._children = null;       
    }
    if(children)
      children.forEach(expand);
}

function expandAll(){
    expand(root); 
    update(root);
}

function collapseAll(){
    root.children.forEach(collapse);
    collapse(root);
    update(root);
}