Getting access_token (for Bearer auth) from spotify using your app credentials.

spotify.js

const client_id = "YOUR_CLIENT_ID"
const client_secret = "YOUR_CLIENT_SECRET"
const refresh_token = "YOUR_REFRESH_TOKEN"

const basic = Buffer.from(`${client_id}:${client_secret}`).toString('base64')

const TOKEN_ENDPOINT = `https://accounts.spotify.com/api/token`

const getAccessToken = async () => {
  const response = await fetch(TOKEN_ENDPOINT, {
    method: 'POST',
    headers: {
      Authorization: `Basic ${basic}`,
      'Content-Type': 'application/x-www-form-urlencoded',
    },
    body: new URLSearchParams({
      grant_type: 'refresh_token',
      refresh_token,
    }),
  })

  return response.json()
}

export const getSpotifyInfo = async (endpoint) => {
  const { access_token } = await getAccessToken()

  return fetch(endpoint, {
    headers: {
      Authorization: `Bearer ${access_token}`,
    },
  })
}

Useful gist🌚