Here is an efficient way to find the maximum character in a string (the character that appears most frequently) and count how many times it appears.
WARNING Note that if there are multiple characters with the same maximum count, this function will return the first one it encounters.
In the maxCharInString function, we first iterate over the string to build a character map where the keys are the characters and the values are the counts.
Then we iterate over the character map to find the character with the maximum count. The function returns an object with the maximum character and its count.