refactor function to improve ordinal suffix handling for 0 [4-9] [11-13]

Author: AkliluMihtsun

practice-tdd/get-ordinal-number.js

@@ -1,13 +1,23 @@
 export function getOrdinalNumber(num) {
   const numStr = num.toString();
   const numLength = numStr.length;
+  const pattern1 = /^(11|12|13)$/;
+  const pattern2 = /^0$/;
+  const pattern3 = /^(4|5|6|7|8|9)$/;
+  const last2digits = numStr.slice(-2);
+  const last1digit = numStr.slice(-1);
+
   if (numStr[numLength - 1] == "1" && numStr[numLength - 2] != "1") {
     return `${numStr}st`;
   } else if (numStr[numLength - 1] == "2" && numStr[numLength - 2] != "1") {
     return `${numStr}nd`;
   } else if (numStr[numLength - 1] == "3" && numStr[numLength - 2] != "1") {
     return `${numStr}rd`;
+  } else if (
+    pattern1.test(last2digits) ||
+    pattern2.test(last1digit) ||
+    pattern3.test(last1digit)
+  ) {
+    return `${numStr}th`;
   }
-
-  //return "1st";
 }