直接上代码

function randomString(length) {
  let out = "";
  let str = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
  for (let i = 0; i < length; i++) {
    out += str.charAt(Math.floor(Math.random() * str.length));
  }
  return out;
}
//头条@Plzbefat
console.log(randomString(10));