Implement getOrdinalNumber with tests

Author: eyob-tech

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

@@ -1,5 +1,20 @@
 function getOrdinalNumber(num) {
-  return "1st";
+  const lastTwoDigits = num % 100;
+  const lastDigit = num % 10;
+
+  if (lastTwoDigits >= 11 && lastTwoDigits <= 13) {
+    return `${num}th`;
+  }
+
+  if (lastDigit === 1) {
+    return `${num}st`;
+  } else if (lastDigit === 2) {
+    return `${num}nd`;
+  } else if (lastDigit === 3) {
+    return `${num}rd`;
+  } else {
+    return `${num}th`;
+  }
 }
 
-module.exports = getOrdinalNumber;
+module.exports = getOrdinalNumber;

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

@@ -2,7 +2,7 @@ const getOrdinalNumber = require("./get-ordinal-number");
 // In this week's prep, we started implementing getOrdinalNumber.
 
 // Continue testing and implementing getOrdinalNumber for additional cases.
-// Write your tests using Jest — remember to run your tests often for continual feedback.
+// Write your tests using Jest - remember to run your tests often for continual feedback.
 
 // To ensure thorough testing, we need broad scenarios that cover all possible cases.
 // Listing individual values, however, can quickly lead to an unmanageable number of test cases.
@@ -18,3 +18,43 @@ test("should append 'st' for numbers ending with 1, except those ending with 11"
   expect(getOrdinalNumber(21)).toEqual("21st");
   expect(getOrdinalNumber(131)).toEqual("131st");
 });
+
+// Case 2: Numbers ending with 2 (but not 12)
+// When the number ends with 2, except those ending with 12,
+// Then the function should return a string by appending "nd" to the number.
+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");
+});
+
+// Case 3: Numbers ending with 3 (but not 13)
+// When the number ends with 3, except those ending with 13,
+// Then the function should return a string by appending "rd" to the number.
+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");
+});
+
+// Case 4: Numbers ending with 11, 12, or 13
+// When the number ends with 11, 12, or 13,
+// Then the function should return a string by appending "th" to the number.
+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");
+  expect(getOrdinalNumber(111)).toEqual("111th");
+  expect(getOrdinalNumber(112)).toEqual("112th");
+  expect(getOrdinalNumber(113)).toEqual("113th");
+});
+
+// Case 5: All other numbers
+// When the number ends with 0, or 4 through 9,
+// Then the function should return a string by appending "th" to the number.
+test("should append 'th' for all other numbers", () => {
+  expect(getOrdinalNumber(4)).toEqual("4th");
+  expect(getOrdinalNumber(10)).toEqual("10th");
+  expect(getOrdinalNumber(100)).toEqual("100th");
+  expect(getOrdinalNumber(0)).toEqual("0th");
+});