implement function to count character occurrences, including case-sensitive and non-alphabet characters

Author: fayaz551

Sprint-3/2-practice-tdd/count.js

@@ -1,5 +1,18 @@
 function countChar(stringOfCharacters, findCharacter) {
-  return 5
+  if (typeof stringOfCharacters !== "string") {
+    throw new Error("First argument must be a string");
+  }
+  if (typeof findCharacter !== "string" || findCharacter.length !== 1) {
+    throw new Error("Second argument must be a single character");
+  }
+
+  let count = 0;
+  for (const char of stringOfCharacters) {
+    if (char === findCharacter) {
+      count++;
+    }
+  }
+  return count;
 }
 
-module.exports = countChar;
+module.exports = countChar;

Sprint-3/2-practice-tdd/count.test.js

@@ -28,3 +28,27 @@ test("should return 0 when the character does not occur in the string", () => {
   const count = countChar(str, char);
   expect(count).toEqual(0);
 }); 
+
+// Case: Case sensitivity
+test("should count characters in a case-sensitive way", () => {
+  const str = "Hello World";
+  const char = "h"; // lowercase 'h' does not match 'H'
+  const count = countChar(str, char);
+  expect(count).toEqual(0);
+});
+
+// Case: Non-alphabet characters
+test("should count non-alphabet characters", () => {
+  const str = "123!@#123!";
+  const char = "1";
+  const count = countChar(str, char);
+  expect(count).toEqual(2);
+});
+
+// Case: Spaces
+test("should count spaces correctly", () => {
+  const str = "a b c d e f g";
+  const char = " ";
+  const count = countChar(str, char);
+  expect(count).toEqual(6);
+});