diff --git a/src/xy/__tests__/xySortX.test.ts b/src/xy/__tests__/xySortX.test.ts
index 9ca42280..5652d9a4 100644
--- a/src/xy/__tests__/xySortX.test.ts
+++ b/src/xy/__tests__/xySortX.test.ts
@@ -43,3 +43,19 @@ test('sorted reverse', () => {
     y: Float64Array.from([3, 2, 1]),
   });
 });
+
+test('typed XY arrays', () => {
+  const data = {
+    x: Float64Array.from([
+      1.557, 1.265, 1.535, 1.622, 2, 1.426, 1.094, 1.201, 1.825,
+    ]),
+    y: Float64Array.from([0, 1, 2, 5, 6, 7, 8, 9, 10]),
+  };
+  const result = xySortX(data);
+  expect(result).toStrictEqual({
+    x: Float64Array.from([
+      1.094, 1.201, 1.265, 1.426, 1.535, 1.557, 1.622, 1.825, 2,
+    ]),
+    y: Float64Array.from([8, 9, 1, 7, 2, 0, 5, 10, 6]),
+  });
+});
diff --git a/src/xy/utils/integral.test.ts b/src/xy/utils/__tests__/integral.test.ts
similarity index 92%
rename from src/xy/utils/integral.test.ts
rename to src/xy/utils/__tests__/integral.test.ts
index 0834a0d4..4bac56da 100644
--- a/src/xy/utils/integral.test.ts
+++ b/src/xy/utils/__tests__/integral.test.ts
@@ -1,6 +1,6 @@
 import { expect, test } from 'vitest';
 
-import integral from './integral';
+import integral from '../integral';
 
 test('should compute expect(integral with a,b, x0 and x1', () => {
   expect(integral(0, 1, 1, 0)).toBe(0.5);
diff --git a/src/xy/xySortX.ts b/src/xy/xySortX.ts
index e240dfd0..1766a425 100644
--- a/src/xy/xySortX.ts
+++ b/src/xy/xySortX.ts
@@ -24,12 +24,10 @@ export function xySortX(data: DataXY): DataXY<Float64Array> {
     }
   }
 
-  const xyObject = (x as number[])
-    .map((val, index) => ({
-      x: val,
-      y: y[index],
-    }))
-    .sort((a, b) => a.x - b.x);
+  const xyObject = Array.from(x, (val, index) => ({
+    x: val,
+    y: y[index],
+  })).sort((a, b) => a.x - b.x);
 
   const response = {
     x: new Float64Array(x.length),