challenge-algorithms-v2.0-andrea-matsunaga/09-mostRepeatedChar/index.js

export function mostUsedChar(text) {
    let charObj = {};
    let maxCount = 0;
    let maxChar = "";

    for (let char of text) {
        charObj[char] = ++charObj[char] || 1;
    }

    for (let char in charObj) {
        if (charObj[char] > maxCount) {
            maxCount = charObj[char];
            maxChar = char;
        }
    }

    return maxChar;
}