diff --git a/src/sliceActions/intersectionsToShapes.js b/src/sliceActions/intersectionsToShapes.js
index f06e7c0..3081dc5 100644
--- a/src/sliceActions/intersectionsToShapes.js
+++ b/src/sliceActions/intersectionsToShapes.js
@@ -87,7 +87,7 @@ export default function intersectionsToShapes(layerIntersectionIndexes, layerInt
         index = firstPoints[0];
 
         while (index !== -1) {
-          if (firstPoints.indexOf(index) === -1) {
+          if (!firstPoints.includes(index)) {
             const intersection = intersectionPoints[index];
             shape.unshift(intersection);
 
diff --git a/src/sliceActions/optimizePaths.js b/src/sliceActions/optimizePaths.js
index 2e69933..00b2b41 100644
--- a/src/sliceActions/optimizePaths.js
+++ b/src/sliceActions/optimizePaths.js
@@ -95,7 +95,7 @@ function optimizeShape(shape, start) {
     let pathIndex;
 
     for (let i = 0; i < inputPaths.length; i ++) {
-      if (donePaths.indexOf(i) !== -1) continue;
+      if (donePaths.includes(i)) continue;
 
       const path = inputPaths[i];