TDD: implement getOrdinalNumber with category tests

Author: salahalsabhi

practice-tdd/get-ordinal-number.js

@@ -1,3 +1,11 @@
 export function getOrdinalNumber(num) {
-  return "1st";
+  return num % 100 === 11 || num % 100 === 12 || num % 100 === 13
+    ? `${num}th`
+    : num % 10 === 1
+      ? `${num}st`
+      : num % 10 === 2
+        ? `${num}nd`
+        : num % 10 === 3
+          ? `${num}rd`
+          : `${num}th`;
 }

practice-tdd/get-ordinal-number.test.js

@@ -18,3 +18,33 @@ test("should append 'st' for numbers ending with 1, except those ending with 11"
   expect(getOrdinalNumber(21)).toEqual("21st");
   expect(getOrdinalNumber(131)).toEqual("131st");
 });
+
+test("should append 'nd' for numbers ending with 2, except those ending with 12", () => {
+  expect(getOrdinalNumber(2)).toEqual("2nd");
+  expect(getOrdinalNumber(22)).toEqual("22nd");
+  expect(getOrdinalNumber(132)).toEqual("132nd");
+});
+
+test("should append 'rd' for numbers ending with 3, except those ending with 13", () => {
+  expect(getOrdinalNumber(3)).toEqual("3rd");
+  expect(getOrdinalNumber(23)).toEqual("23rd");
+  expect(getOrdinalNumber(133)).toEqual("133rd");
+});
+
+test("should append 'th' for numbers ending with 11, 12, or 13.", () => {
+  expect(getOrdinalNumber(11)).toEqual("11th");
+  expect(getOrdinalNumber(12)).toEqual("12th");
+  expect(getOrdinalNumber(13)).toEqual("13th");
+});
+
+test("should append 'th' for numbers ending with 0, 4, or big numbers.", () => {
+  expect(getOrdinalNumber(10)).toEqual("10th");
+  expect(getOrdinalNumber(30)).toEqual("30th");
+  expect(getOrdinalNumber(500)).toEqual("500th");
+  expect(getOrdinalNumber(4)).toEqual("4th");
+  expect(getOrdinalNumber(44)).toEqual("44th");
+  expect(getOrdinalNumber(134)).toEqual("134th");
+  expect(getOrdinalNumber(987535)).toEqual("987535th");
+  expect(getOrdinalNumber(111)).toEqual("111th");
+  expect(getOrdinalNumber(112)).toEqual("112th");
+});