Implement getOrdinalNumber with TDD

Author: KhotKeys

Sprint-3/2-practice-tdd/get-ordinal-number.js

@@ -1,5 +1,11 @@
 function getOrdinalNumber(num) {
-  return "1st";
+  const lastTwo = num % 100;
+  const lastOne = num % 10;
+  if (lastTwo >= 11 && lastTwo <= 13) return `${num}th`;
+  if (lastOne === 1) return `${num}st`;
+  if (lastOne === 2) return `${num}nd`;
+  if (lastOne === 3) return `${num}rd`;
+  return `${num}th`;
 }
 
 module.exports = getOrdinalNumber;