#routes.js
app.post('/api/account/edit/:field/:optional?', isAuthenticated, function (req, res) {
    var token = req.headers.authorization.split(' ')[1]
    userUtils.getUserIdFromToken(token)
    .then(userId => {
      console.log('userId: ', userId)
      utils.modifyUserFieldData(userId)
      .then(out1 => {
        console.log('out1: ', out1)
        return res.status(200)
      })
    })

    .catch(err => {
      console.log('err: ', err)
      return res.status(500)
    })
  })

#userUtils.js
function getUserIdFromToken (token) {
  promise.try(() => jwt.verify(token, process.env.JWT_SECRET))
  .then(result => {
    console.log('result: ', result.id)
    promise.resolve(result.id)
  })
  .catch(jwt.JsonWebTokenError, err => {
    console.log('error: ', err)
  })
  .catch(jwt.NotBeforeError, err => {
    console.log('error: ', err)
  })
  .catch(jwt.TokenExpiredError, err => {
    console.log('error: ', err)
  })
  .catch(err => {
    console.log('error: ', err)
  })
}
module.exports.getUserIdFromToken = getUserIdFromToken