Function angle

d3-3.2.8/d3.js:2364–2366

(λ0, λ1)

      p0 = null;
    }
    function angle(λ0, λ1) {
      return (λ1 -= λ0) < 0 ? λ1 + 360 : λ1;
    }
    function compareRanges(a, b) {
      return a[0] - b[0];
    }