Error: Cannot find module 'express-jwt' code example

Example: express jwt

// JWT MIDDLEWARE
const jwt = require('jsonwebtoken')
const httpError = require('http-errors')

module.exports = (req, res, next) => {
  try {
    const tokenHeader = req.headers.authorization.split('Bearer ')[1]
    const decoded = jwt.verify(tokenHeader, process.env.ACCESS_TOKEN_SECRET)
    req.user = decoded
    next()
  } catch (err) {
    next(httpError(401))
  }
}

// ROUTE LOGIN
app.get('/protect', authJwt, (req, res) => {
  console.log(req.user)
  res.send('aim in proteced route')
})

app.post('/login', (req, res) => {
  const bodyPayload = {
    id: Date.now(),
    username: req.body.username
  }
  const token = signAccessToken(res, bodyPayload)
  return res.status(200).json(token)
})

app.post('/refresh-token', (req, res) => {
  const refreshToken = signRefreshToken(req)
  res.status(200).json(refreshToken)
  res.end()
})

// JWT HELPER
const jwt = require('jsonwebtoken')
const httpError = require('http-errors')

exports.signAccessToken = (res, payload) => {
  try {
    if (payload) {
      const accessToken = jwt.sign({ ...payload }, process.env.ACCESS_TOKEN_SECRET, { expiresIn: '1m' })
      const refreshToken = jwt.sign({ ...payload }, process.env.REFRESH_TOKEN_SECRET, { expiresIn: '90d' })
      res.cookie('refreshToken', `${refreshToken}`, { expired: 86400 * 90 })
      return { accessToken, refreshToken }
    }
  } catch (err) {
    return httpError(500, err)
  }
}

exports.signRefreshToken = (req) => {
  try {
    const getToken = req.cookies.refreshToken
    if (getToken) {
      const { id, username } = jwt.verify(getToken, process.env.REFRESH_TOKEN_SECRET)
      const accesssToken = jwt.sign({ id, username }, process.env.ACCESS_TOKEN_SECRET, { expiresIn: '1m' })
      return { accesssToken }
    }
  } catch (err) {
    return httpError(401, err)
  }
}