SOURCE

const str = "aaabbbcccc";
function findStr(str) {
    const obj = {};
    for (let index = 0; index < str.length; index++) {
        const element = str[index];
        obj[element] = obj[element] + 1 || 1
    }
    // 找出出现最多的字符和次数
    const maxNum = Math.max(...Object.values(obj))  //拿到次数
    const arr = []
    for (const key in obj) {
        if (obj[key] === maxNum) {
            arr.push({ chart: key, count: obj[key] })
        }
    }
    return arr
}

console.log(findStr(str));