diff --git a/reverse-inside-parentheses-inside-parentheses/index.js b/reverse-inside-parentheses-inside-parentheses/index.js
new file mode 100644
index 0000000..032d510
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+++ b/reverse-inside-parentheses-inside-parentheses/index.js
@@ -0,0 +1,18 @@
+// https://www.codewars.com/kata/reverse-inside-parentheses-inside-parentheses/javascript
+
+const reverseInParens = str => {
+  const rb = /[\[\]]/g;
+  const rm = /\([^\(\)]*\)/;
+  const mi = {'[':']', ']':'['};
+  const mc = {'[':'(', ']':')'};
+  let last;
+  while (last !== str) {
+    last = str;
+    str = str.replace(rm, s => {
+      s = s.substr(1, s.length-2).replace(rb, s => mi[s]);
+      return [']',...s,'['].reverse().join``;
+    });
+  }
+  str = str.replace(rb, s => mc[s]);
+  return str;
+};