import “selection”;

d3_selectionPrototype.each = function(callback) {

return d3_selection_each(this, function(node, i, j) {
  callback.call(node, node.__data__, i, j);
});

};

function d3_selection_each(groups, callback) {

for (var j = 0, m = groups.length; j < m; j++) {
  for (var group = groups[j], i = 0, n = group.length, node; i < n; i++) {
    if (node = group[i]) callback(node, i, j);
  }
}
return groups;

}