Get recently played Spotify Track in serverless function running on vercel

last-played-spotify-song.js

const axios = require('axios')

const spotifyAPIBaseUri = 'https://api.spotify.com'
const spotifyAccountsBaseUri = 'https://accounts.spotify.com'

const {
  SPOTIFY_CLIENT_ID, // Your Spotify OAuth Client ID
  SPOTIFY_CLIENT_SECRET, // Spotify OAuth Client Secret
  SPOTIFY_REFRESH_TOKEN, // Your personal refresh token (you have to authenticate yourself against your app once to receive this)
} = process.env

let accessToken = ''

axios.defaults.withCredentials = true
axios.defaults.headers.common['Content-Type'] = 'application/json'

const refreshAccessToken = () => {
  const headers = {
    'Content-Type': 'application/x-www-form-urlencoded',
    Authorization: `Basic ${new Buffer.from(
      `${SPOTIFY_CLIENT_ID}:${SPOTIFY_CLIENT_SECRET}`
    ).toString('base64')}`,
  }

  return axios
    .post(
      `${spotifyAccountsBaseUri}/api/token`,
      `grant_type=refresh_token&refresh_token=${SPOTIFY_REFRESH_TOKEN}`,
      {
        headers: headers,
      }
    )
    .then(response => {
      accessToken = response.data.access_token
    })
}

const getRecentlyPlayedTrack = () => {
  const headers = accessToken
    ? {
        Authorization: `Bearer ${accessToken}`,
      }
    : {}

  return axios.get(
    `${spotifyAPIBaseUri}/v1/me/player/recently-played?limit=1`,
    {
      headers: headers,
    }
  )
}

export default (req, res) => {
  getRecentlyPlayedTrack()
    .then(({ data }) => {
      res.send(data)
    })
    .catch(e => {
      refreshAccessToken()
        .then(() => {
          getRecentlyPlayed()
            .then(({ data }) => {
              res.send(data)
            })
            .catch(e => {
              res.status(500).send('Failed to get recently played track')
            })
        })
        .catch(e => {
          res.status(500).send('Failed to refresh token')
        })
    })
}