Function d3_functor

explainshell/web/static/js/d3.v3.js:1616–1620

(v)

    d3_rgb_names.set(key, d3_rgb_parse(value, d3_rgb, d3_hsl_rgb));
  });
  function d3_functor(v) {
    return typeof v === "function" ? v : function() {
      return v;
    };
  }
  d3.functor = d3_functor;
  function d3_identity(d) {
    return d;