src/arrays/median.js

import "../math/number";
import "ascending";
import "quantile";

d3.median = function(array, f) {
  if (arguments.length > 1) array = array.map(f);
  array = array.filter(d3_number);
  return array.length ? d3.quantile(array.sort(d3.ascending), .5) : undefined;
};