思路
比较相邻两个的字符的码点，如果差值在1，就是连续的，然后拼接字符串放到数组中
const test = '1212345689';
const continuityKeyWord = [];
function isContinuity(a, b) {
return b.codePointAt() - a.codePointAt() == 1;
}
let keyword = test[0];
for (let i in test) {
if (i > 0 && isContinuity(test[i - 1], test[i])) {
keyword += test[i];
} else {
if (keyword.length > 1) continuityKeyWord.push(keyword);
keyword = test[i];
}
}
if (keyword.length > 1) continuityKeyWord.push(keyword);
console.log(continuityKeyWord, Math.max(...continuityKeyWord));
