functionfindLongest(str) {
if (!str) return {}
let count = 0let maxCount = 0let cur = str[0]
let res = {}
for (let i = 0; i < str.length; i++) {
const s = str[i]
if (s === cur) {
count++
if (count > maxCount) {
res = { [s]: count }
maxCount = count
}
if (count === maxCount) {
res[s] = count
}
} else {
count = 1
cur = s
}
}
return res
}