littledian

const getUserInfo = (function() {
  let userInfo = null
  let promise = null
  return function(cb) {
    if (!userInfo && !promise) {
      promise = new Promise(resolve => {
        setTimeout(() => {
          userInfo = {username: 'littledian'}
          resolve()
          cb && cb(userInfo)

littledian

function generateRandomPassword() {
  const randomChar = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'
  const randomNum = '0123456789'
  const randomSymbol = '!@#$%^&*()'

  const getRandomChar = () => randomChar[Math.floor(Math.random() * randomChar.length)]
  const getRandomNum = () => randomNum[Math.floor(Math.random() * randomNum.length)]
  const getRandomSymbol = () => randomSymbol[Math.floor(Math.random() * randomSymbol.length)]

  const passwordLength = 8