D3 v4 - 访问选择数组并找到相应的元素

Question

I'm trying to get a constraint relaxing to work for my piechart. It is based on this example https://jsfiddle.net/thudfactor/HdwTH/ but the relaxing method used seems not to work with v4 any more.
The concrete problem is how they access the selection group array directly:

textLabels = labelGroups.append("text").attr( ... );

if(again) {
        labelElements = textLabels[0];     <------------- here
        textLines.attr("y2",function(d,i) {
            labelForLine = d3.select(labelElements[i]);
            return labelForLine.attr("y");
        });
        setTimeout(relax,20)
    }

Has it changed with D3 v4.x how you access a selections group array?
How would you go about it now?

Answer 1

In D3 4.0, selections are not arrays anymore. According to the API:

Selections no longer subclass Array using prototype chain injection; they are now plain objects, improving performance.

So, if you console.log(textLabels) , you're gonna see something like this:

{_groups: Array[1], _parents: Array[1]}

Depending on exactly what are you selecting. From there, you can access your array using textLabels._groups , for instance.

For having an array, you have to use selection.nodes() , which, according to the API:

Returns an array of all (non-null) elements in this selection.