Sort two arrays

sort-two-arrays/index.js

@@ -0,0 +1,17 @@
+// https://www.codewars.com/kata/sort-two-arrays/javascript
+
+function sortArrays(a1, a2) {
+  return [sortUsing(a1, a2), sortUsing(a2, a1)];
+}
+
+// https://gist.github.com/gkucmierz/cbfd265a699b3f36c609453289363f49
+function sortUsing(a1, a2) {
+  const a = [];
+  for (let i = 0; i < a1.length; ++i) {
+    a[i] = [a1[i], a2[i], i];
+  }
+  return a.sort((a, b) => {
+    const d = a[1]-b[1];
+    return d === 0 ? a[2]-b[2] : d;
+  }).map(a => a[0]);
+}