1 d3.scale.quantile = function() {

     2   return d3_scale_quantile([], []);

     3 };

     4 

     5 function d3_scale_quantile(domain, range) {

     6   var thresholds;

     7 

     8   function rescale() {

     9     var k = 0,

    10         n = domain.length,

    11         q = range.length;

    12     thresholds = [];

    13     while (++k < q) thresholds[k - 1] = d3.quantile(domain, k / q);

    14     return scale;

    15   }

    16 

    17   function scale(x) {

    18     if (isNaN(x = +x)) return NaN;

    19     return range[d3.bisect(thresholds, x)];

    20   }

    21 

    22   scale.domain = function(x) {

    23     if (!arguments.length) return domain;

    24     domain = x.filter(function(d) { return !isNaN(d); }).sort(d3.ascending);

    25     return rescale();

    26   };

    27 

    28   scale.range = function(x) {

    29     if (!arguments.length) return range;

    30     range = x;

    31     return rescale();

    32   };

    33 

    34   scale.quantiles = function() {

    35     return thresholds;

    36   };

    37 

    38   scale.copy = function() {

    39     return d3_scale_quantile(domain, range); // copy on write!

    40   };

    41 

    42   return rescale();

    43 };