如何从d3选择中获取d3实例？

Question

I have a method that gets a d3 selection as an argument:

function foo(selection){

}

Inside that function I need the d3 instance. Instead of passing the d3 instance as an extra argument I would like to get it from the selection. Is that possible?

function foo(selection){
    var d3 = selection.getD3();
    var element = document.createElement('div');
    d3.select(element);
}

Edit

The methods provided by the selection do not include something like "getD3":

append
attr
call
classed
clone
constructor
data
datum
dispatch
each
empty
enter
exit
filter
html
insert
interrupt
lower
merge
node
nodes
on
order
property
raise
remove
select
selectAll
size
sort
style
text
transition

Answer 1

You can add a reference to d3 by adding it to the selection object

var mySelection = d3.selectAll('your_selection_criteria');

mySelection.d3_reference = d3;  //mySelection is a JSON object, so
                                // you can attach anything to it

foo(mySelection);


function foo(selection) {
    var myD3 = selection.d3_reference;
    // now myD3 is d3
}