Function withinRange

d3-3.2.8/d3.js:2370–2372

(x, range)

      return a[0] - b[0];
    }
    function withinRange(x, range) {
      return range[0] <= range[1] ? range[0] <= x && x <= range[1] : x < range[0] || range[1] < x;
    }
    return function(feature) {
      φ1 = λ1 = -(λ0 = φ0 = Infinity);
      ranges = [];