Solution

src/formatDate.js

@@ -7,8 +7,52 @@
  *
  * @returns {string}
  */
-function formatDate(date, fromFormat, toFormat) {
-  // write code here
-}
+function formatDate(date, fromDate, toDate) {
+  const indexDd = fromDate.indexOf('DD');
+  const indexMm = fromDate.indexOf('MM');
+  const indexYyyy = fromDate.indexOf('YYYY');
+  const indexYy = fromDate.indexOf('YY');
+
+  const dateArr = date.split(fromDate[3]);
+
+  const dd = dateArr[indexDd];
+  const mm = dateArr[indexMm];
+  let yyyy = dateArr[indexYyyy];
+  let yy = dateArr[indexYy];
+
+  if (fromDate.indexOf('YYYY') === -1) {
+    if (yy < 30) {
+      yyyy = '20' + yy;
+    } else {
+      yyyy = '19' + yy;
+    }
+  } else {
+    yy = yyyy.slice(-2);
+  }
 
+  let newFormatDate = '';
+
+  for (let i = 0; i < toDate.length - 1; i++) {
+    switch (toDate[i]) {
+      case 'DD':
+        newFormatDate += dd;
+        break;
+      case 'MM':
+        newFormatDate += mm;
+        break;
+      case 'YYYY':
+        newFormatDate += yyyy;
+        break;
+      case 'YY':
+        newFormatDate += yy;
+        break;
+    }
+
+    if (i !== toDate.length - 2) {
+      newFormatDate += toDate[3];
+    }
+  }
+
+  return newFormatDate;
+}
 module.exports = formatDate;