function randomString(length) {
let str = ‘0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ‘;
let result = ‘‘;
for (let i = length; i > 0; --i)
result += str[Math.floor(Math.random() * str.length)];
return result;
}
原文：https://www.cnblogs.com/zhenjianyu/p/14669344.html