const uuids = []
function getGuid(size) {
  if (size) size--;
  const uidLen = 13; // 机器码有多少位
  const uidText = '1234567890'
  let uid = ''; // 定义空变量用来接收机器码
  for (let i = 0; i < uidLen; i++)  uid += uidText.charAt(Math.floor(Math.random() * uidText.length)); //循环机器码位数随机填充
  let uuid = new Date().valueOf() + uid
  if (uuids && uuids.find(function (o) { return o === uuid })) {
    uuid = !size ? new Date().valueOf() : getGuid(5)
  }

  uuids.push(uuid)
  if (uuids.length > 300) uuids.length = 0
  return uuid
}


// for (let index = 0; index < 10; index++) {
//   console.log(getGuid(uuids));
// }


const list = ["a", "b", "c"];

let index = list.findIndex((x) => x == "e");

console.log(index); // 1