js 生成随机字符串

// Random user password
function randomPassword(length) {
  length = Number(length);
  // Limit length
  // 最短6位，最长16位
  if (length < 6) {
    length = 6;
  } else if (length > 16) {
    length = 16;
  }
  let passwordArray = [
    "ABCDEFGHIJKLMNOPQRSTUVWXYZ",
    "abcdefghijklmnopqrstuvwxyz",
    "1234567890",
    "!@#$%&*()",
  ];
  var password = [];
  let n = 0;
  for (let i = 0; i < length; i++) {
    // If password length less than 9, all value random
    if (password.length < length - 4) {
      // Get random passwordArray index
      let arrayRandom = Math.floor(Math.random() * 4);
      // Get password array value
      let passwordItem = passwordArray[arrayRandom];
      // Get password array value random index
      // Get random real value
      let item = passwordItem[Math.floor(Math.random() * passwordItem.length)];
      password.push(item);
    } else {
      // If password large then 9, lastest 4 password will push in according to the random password index
      // Get the array values sequentially
      let newItem = passwordArray[n];
      let lastItem = newItem[Math.floor(Math.random() * newItem.length)];
      // Get array splice index
      let spliceIndex = Math.floor(Math.random() * password.length);
      password.splice(spliceIndex, 0, lastItem);
      n++;
    }
  }
  return password.join("");
}

function createPassword(min, max) {
  //可以生成随机密码的相关数组
  var num = ["0", "1", "2", "3", "4", "5", "6", "7", "8", "9"];
  var english = [
    "a",
    "b",
    "c",
    "d",
    "e",
    "f",
    "g",
    "h",
    "i",
    "j",
    "k",
    "l",
    "m",
    "n",
    "o",
    "p",
    "q",
    "r",
    "s",
    "t",
    "u",
    "v",
    "w",
    "x",
    "y",
    "z",
  ];
  var ENGLISH = [
    "A",
    "B",
    "C",
    "D",
    "E",
    "F",
    "G",
    "H",
    "I",
    "J",
    "K",
    "L",
    "M",
    "N",
    "O",
    "P",
    "Q",
    "R",
    "S",
    "T",
    "U",
    "V",
    "W",
    "X",
    "Y",
    "Z",
  ];
  var special = ["-", "_", "#"];
  var config = num.concat(english).concat(ENGLISH).concat(special);

  //先放入一个必须存在的
  var arr = [];
  arr.push(getOne(num));
  arr.push(getOne(english));
  arr.push(getOne(ENGLISH));
  arr.push(getOne(special));

  //获取需要生成的长度
  var len = min + Math.floor(Math.random() * (max - min + 1));

  for (var i = 4; i < len; i++) {
    //从数组里面抽出一个
    arr.push(config[Math.floor(Math.random() * config.length)]);
  }

  //乱序
  var newArr = [];
  for (var j = 0; j < len; j++) {
    newArr.push(arr.splice(Math.random() * arr.length, 1)[0]);
  }

  //随机从数组中抽出一个数值
  function getOne(arr) {
    return arr[Math.floor(Math.random() * arr.length)];
  }

  return newArr.join("");
}