Index: node_modules/d3-contour/src/contains.js
===================================================================
--- node_modules/d3-contour/src/contains.js	(revision e4c61dd6cd86e06265bc2bd91adba84a0f04044a)
+++ node_modules/d3-contour/src/contains.js	(revision e4c61dd6cd86e06265bc2bd91adba84a0f04044a)
@@ -0,0 +1,27 @@
+export default function(ring, hole) {
+  var i = -1, n = hole.length, c;
+  while (++i < n) if (c = ringContains(ring, hole[i])) return c;
+  return 0;
+}
+
+function ringContains(ring, point) {
+  var x = point[0], y = point[1], contains = -1;
+  for (var i = 0, n = ring.length, j = n - 1; i < n; j = i++) {
+    var pi = ring[i], xi = pi[0], yi = pi[1], pj = ring[j], xj = pj[0], yj = pj[1];
+    if (segmentContains(pi, pj, point)) return 0;
+    if (((yi > y) !== (yj > y)) && ((x < (xj - xi) * (y - yi) / (yj - yi) + xi))) contains = -contains;
+  }
+  return contains;
+}
+
+function segmentContains(a, b, c) {
+  var i; return collinear(a, b, c) && within(a[i = +(a[0] === b[0])], c[i], b[i]);
+}
+
+function collinear(a, b, c) {
+  return (b[0] - a[0]) * (c[1] - a[1]) === (c[0] - a[0]) * (b[1] - a[1]);
+}
+
+function within(p, q, r) {
+  return p <= q && q <= r || r <= q && q <= p;
+}