diff --git a/index.js b/index.js
index 850cdb6..c6aafba 100644
--- a/index.js
+++ b/index.js
@@ -67,10 +67,9 @@ function hash(string) {
 // randomly returns either 1 or -1
 const randSign = () => (Math.random() < 0.5 ? 1 : -1);
 const shift = () => randSign() * Math.random() * 1e-7;
-const range = n => new Array(n).fill(0).map((_, i) => i);
 const shiftRing = ring => ring.map(([x, y]) => [x + shift(), y + shift()]);
-const shiftPolygon = rings.map(shiftRing);
-const shiftMultiPolygon = polygons.map(shiftPolygon);
+const shiftPolygon = rings => rings.map(shiftRing);
+const shiftMultiPolygon = polygons => polygons.map(shiftPolygon);
 function shiftGeometry(geometry) {
   if (geometry.type === "Polygon") {
     geometry.coordinates = shiftPolygon(geometry.coordinates);
diff --git a/zonal.js b/zonal.js
index 0b494a9..37ed72c 100644
--- a/zonal.js
+++ b/zonal.js
@@ -111,12 +111,6 @@ var shift = function shift() {
   return randSign() * Math.random() * 1e-7;
 };
 
-var range = function range(n) {
-  return new Array(n).fill(0).map(function (_, i) {
-    return i;
-  });
-};
-
 var shiftRing = function shiftRing(ring) {
   return ring.map(function (_ref2) {
     var _ref3 = _slicedToArray(_ref2, 2),
@@ -127,8 +121,13 @@ var shiftRing = function shiftRing(ring) {
   });
 };
 
-var shiftPolygon = rings.map(shiftRing);
-var shiftMultiPolygon = polygons.map(shiftPolygon);
+var shiftPolygon = function shiftPolygon(rings) {
+  return rings.map(shiftRing);
+};
+
+var shiftMultiPolygon = function shiftMultiPolygon(polygons) {
+  return polygons.map(shiftPolygon);
+};
 
 function shiftGeometry(geometry) {
   if (geometry.type === "Polygon") {
diff --git a/zonal.min.js b/zonal.min.js
index e848ef0..4e9a9e2 100644
--- a/zonal.min.js
+++ b/zonal.min.js
@@ -5647,12 +5647,6 @@ var shift = function shift() {
   return randSign() * Math.random() * 1e-7;
 };
 
-var range = function range(n) {
-  return new Array(n).fill(0).map(function (_, i) {
-    return i;
-  });
-};
-
 var shiftRing = function shiftRing(ring) {
   return ring.map(function (_ref2) {
     var _ref3 = _slicedToArray(_ref2, 2),
@@ -5663,8 +5657,13 @@ var shiftRing = function shiftRing(ring) {
   });
 };
 
-var shiftPolygon = rings.map(shiftRing);
-var shiftMultiPolygon = polygons.map(shiftPolygon);
+var shiftPolygon = function shiftPolygon(rings) {
+  return rings.map(shiftRing);
+};
+
+var shiftMultiPolygon = function shiftMultiPolygon(polygons) {
+  return polygons.map(shiftPolygon);
+};
 
 function shiftGeometry(geometry) {
   if (geometry.type === "Polygon") {