Ex7 b

ex7/ex7.js

@@ -1,6 +1,6 @@
 /**
- * Write a function that returns the character that repeats itself the most in
- * a given string. If there isn't one, returns null.
+ * mostFrequentChar returns the character that repeats itself the most in str. 
+ * If there isn't one, returns null.
  *
  * For example:
  * mostFrequentChar("zuriel yahav") === "a"
@@ -9,3 +9,70 @@
  * mostFrequentChar("a b c d e f") === " "
  * mostFrequentChar("") === null
  */
+
+function mostFrequentChar(str) {
+
+	objCharCount = {};
+
+	if (str === '') {
+		return null;
+	}
+
+	objCharCount = countChar(str);
+
+	return getFrequentChar(objCharCount);
+}
+
+function getFrequentChar(objCharCount) {
+
+	var maxCount = 0,
+	  frequentChar = null,
+	  frequentCount = 0,
+	  arrayChar = [],
+	  currentCount = 0,
+	  currentChar = '';
+
+	arrayChar = Object.keys(objCharCount);
+
+	for (var i = 0; i < arrayChar.length; i++) {
+
+		currentChar = arrayChar[i];
+		currentCount = objCharCount[currentChar];
+
+		if (maxCount < currentCount) {
+
+			maxCount = currentCount;
+			frequentChar = currentChar;
+
+		} else if (maxCount === currentCount) {
+
+			frequentChar = null;
+
+		}
+	}
+	return frequentChar;
+}
+
+function countChar(str) { 
+
+	var objCharCount = {};
+
+	for (var i = 0; i < str.length; i++) {
+
+		// The char we are now working on
+		currentChar = str.charAt(i); 
+
+		if (objCharCount[currentChar] === undefined) {
+
+			objCharCount[currentChar] = 1;
+
+		} else {
+
+			objCharCount[currentChar] = objCharCount[currentChar] += 1;
+
+		}
+	}
+	return objCharCount;
+}
+
+module.exports = mostFrequentChar; 

ex7/ex7Spec.js

@@ -0,0 +1,24 @@
+var mostFrequentChar= require('./ex7.js');
+
+describe("mostFrequentChar", function() {
+
+	it("finds one char that repeats the most", function(){
+		expect(mostFrequentChar('zuriel yahav')).toBe('a');
+	});
+
+	it("returns null because more than one char repeats twice", function(){
+		expect(mostFrequentChar('ohad kravchick')).toBeNull();
+	});
+
+	it("finds one char that repeats the most (3)", function(){
+		expect(mostFrequentChar('dana kravchick')).toBe('a');
+	});
+
+	it("finds a whitespace as the most frequent char", function(){
+		expect(mostFrequentChar('a b c d e f')).toBe(' ');
+	});
+
+	it("returns null because input is empty", function(){
+		expect(mostFrequentChar('')).toBeNull();
+	});
+});