Function d3_scale_ordinal

explainshell/web/static/js/d3.v3.js:6618–6693

(domain, ranger)

    });
  };
  function d3_scale_ordinal(domain, ranger) {
    var index, range, rangeBand;
    function scale(x) {
      return range[((index.get(x) || index.set(x, domain.push(x))) - 1) % range.length];
    }
    function steps(start, step) {
      return d3.range(domain.length).map(function(i) {
        return start + step * i;
      });
    }
    scale.domain = function(x) {
      if (!arguments.length) return domain;
      domain = [];
      index = new d3_Map();
      var i = -1, n = x.length, xi;
      while (++i < n) if (!index.has(xi = x[i])) index.set(xi, domain.push(xi));
      return scale[ranger.t].apply(scale, ranger.a);
    };
    scale.range = function(x) {
      if (!arguments.length) return range;
      range = x;
      rangeBand = 0;
      ranger = {
        t: "range",
        a: arguments
      };
      return scale;
    };
    scale.rangePoints = function(x, padding) {
      if (arguments.length < 2) padding = 0;
      var start = x[0], stop = x[1], step = (stop - start) / (Math.max(1, domain.length - 1) + padding);
      range = steps(domain.length < 2 ? (start + stop) / 2 : start + step * padding / 2, step);
      rangeBand = 0;
      ranger = {
        t: "rangePoints",
        a: arguments
      };
      return scale;
    };
    scale.rangeBands = function(x, padding, outerPadding) {
      if (arguments.length < 2) padding = 0;
      if (arguments.length < 3) outerPadding = padding;
      var reverse = x[1] < x[0], start = x[reverse - 0], stop = x[1 - reverse], step = (stop - start) / (domain.length - padding + 2 * outerPadding);
      range = steps(start + step * outerPadding, step);
      if (reverse) range.reverse();
      rangeBand = step * (1 - padding);
      ranger = {
        t: "rangeBands",
        a: arguments
      };
      return scale;
    };
    scale.rangeRoundBands = function(x, padding, outerPadding) {
      if (arguments.length < 2) padding = 0;
      if (arguments.length < 3) outerPadding = padding;
      var reverse = x[1] < x[0], start = x[reverse - 0], stop = x[1 - reverse], step = Math.floor((stop - start) / (domain.length - padding + 2 * outerPadding)), error = stop - start - (domain.length - padding) * step;
      range = steps(start + Math.round(error / 2), step);
      if (reverse) range.reverse();