solution

src/formatDate.js

@@ -8,7 +8,33 @@
  * @returns {string}
  */
 function formatDate(date, fromFormat, toFormat) {
-  // write code here
+  const fromSeparate = fromFormat[3];
+  const toSeparate = toFormat[3];
+  const fromFormatDate = fromFormat.slice(0, 3);
+  const toFormatDate = toFormat.slice(0, 3);
+
+  const origDate = date.split(fromSeparate);
+  const origDateObj = {};
+  const returnDate = {};
+
+  for (let i = 0; i < fromFormatDate.length; i++) {
+    origDateObj[fromFormatDate[i]] = origDate[i];
+  }
+
+  if ('YYYY' in origDateObj) {
+    origDateObj['YY'] = origDateObj['YYYY'].slice(2);
+  } else if ('YY' in origDateObj) {
+    origDateObj['YYYY'] =
+      origDateObj['YY'] < 30
+        ? `20${origDateObj['YY']}`
+        : `19${origDateObj['YY']}`;
+  }
+
+  for (let i = 0; i < toFormatDate.length; i++) {
+    returnDate[toFormatDate[i]] = origDateObj[toFormatDate[i]];
+  }
+
+  return Object.values(returnDate).join(toSeparate);
 }
 
 module.exports = formatDate;