diff --git a/codewars/7kyu/mutate-my-strings/koronya.js b/codewars/7kyu/mutate-my-strings/koronya.js
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index 000000000..0636fd78b
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+++ b/codewars/7kyu/mutate-my-strings/koronya.js
@@ -0,0 +1,21 @@
+// [JS][7kyu] Mutate My Strings
+// mutate-my-strings
+// https://www.codewars.com/kata/59bc0059bf10a498a6000025/train/javascript
+
+const mutateMyStrings = (stringOne, stringTwo) => {
+  const result = [stringOne]
+  let prev = stringOne
+  const stringTwoLength = stringTwo.length
+  for (let i = 0; i < stringTwoLength; i += 1 || 0) {
+    const current = prev.split('')
+    current[i] = stringTwo[i]
+    const candiadate = current.join('')
+    if (candiadate !== prev) {
+      result.push(current.join(''))
+    }
+    prev = current.join('')
+  }
+  return result.join('\n') + '\n'
+}
+
+mutateMyStrings('bubble gum', 'turtle ham')