feat(09-mostRepeatedChar): Adiciona função

09-mostRepeatedChar/index.js

@@ -1,4 +1,23 @@
 export function mostUsedChar(text) {
     // implementar logica aqui
-    return ""
+    const charMap = {};
+    let max = 0;
+    let frequentChar = '';
+
+    for (let char of text) {
+        if (charMap[char]){
+            charMap[char]++;
+        } else {
+            charMap[char] = 1;
+        }
+    }
+
+    for (let char in charMap) {
+        if (charMap[char] > max) {
+            max = charMap[char];
+            frequentChar = char;
+        }
+    }
+
+    return frequentChar
 }