Axios Post Error - Connection Refused for Spotify API

Would very much appreciate help figuring out why i am receiving an error in my axios post request. New to using APIs and would also love to know how I can best error handle things like this.

const express = require('express');
const spotifyWebApi = require('spotify-web-api-node');
const cors = require('cors');

const app = express();
const bodyParser = require('body-parser');
app.use(cors())
app.use(bodyParser.json())

app.post('/refresh', (req, res) => {
    const refreshToken = req.body.refreshToken;
    console.log(refreshToken)
    const spotifyApi = new spotifyWebApi({
        redirectUri: 'http://localhost:3000',
        clientId: '34203c820a8a49b783fb4588f1b241df',
        clientSecret: '9343f7f9db05463cbf2c1b9532b9137e',
        refreshToken,
    })

    spotifyApi.refreshAccessToken().then(
    (data) => {
        res.json({
            accessToken: data.body.access_token,
            expiresIn: data.body.expires_in,
        })

    }).catch(err => {
        console.log(err)
        res.sendStatus(400)

    }) 
});
       
app.post('/login', (req, res) => {
    const code = req.body.code;
    const spotifyApi = new spotifyWebApi({
        redirectUri: 'http://localhost:3000',
        clientId: '34203c820a8a49b783fb4588f1b241df',
        clientSecret: /
    })


    spotifyApi.authorizationCodeGrant(code).then(data => {
    res.json({
        accessToken: data.body.access_token,
        refreshToken: data.body.refresh_token,
        expiresIn: data.body.expires_in,
    })

    }).catch(()=> {
    res.sendStatus(400)
    })

});

app.listen(3001);

Please let me know if you need anything else to help me solve this problem.

Tried commenting out catch handle to home page,
following webdev simplified spotify tutorial

Four items are wrong.

#1 You don't need to serve app.post, it needs to change into app.get

The POST API call, will call inside spotifyApi.refreshAccessToken() and spotifyApi.authorizationCodeGrant()

The express just response app.get() for the user's browser access.

The axois POST is not related to this question.

#2 The app.get("/callback") will call by Spotify server, you needs to capture code and forward to the spotifyApi.authorizationCodeGrant(code), that part is missing

#3 You missed set tokens to the spotifyApi.
It helps to get the next access token by refreshAccessToken()

// save access token
spotifyApi.setAccessToken(data.body.access_token);
// save refresh token
spotifyApi.setRefreshToken(data.body.refresh_token);

#4 Miss match Express callback port and redirect port number.

Express use 3001

app.listen(3001);

Redirect URI use 3000

http://localhost:3000

Both should be a match

This demo code will work

Save as demo.js file name.

const SpotifyWebApi = require('spotify-web-api-node')
const express = require("express")
const cors = require("cors")

const app = express()
app.use(cors())

PORT = 3000

const scopes = ['user-read-private', 'user-read-email'] // you need to add a scope, it depends on your API call
const state = 'what-ever-your-state'

var spotifyApi = new SpotifyWebApi({
    clientId: 'your client ID',
    clientSecret: 'your client secret',
    redirectUri: `http://localhost:${PORT}/callback`    // my redirectURL is `localhost:3000/callback`
});

app.get("/login", (request, response) => {
    var authorizeURL = spotifyApi.createAuthorizeURL(scopes, state);
    response.redirect(authorizeURL);
})

app.get("/callback", async (request, response) => {
    const code = request.query["code"]
    spotifyApi.authorizationCodeGrant(code).then(data => {
        // save access token
        spotifyApi.setAccessToken(data.body.access_token);

        // save refresh token
        spotifyApi.setRefreshToken(data.body.refresh_token);

        // show tokens in browser
        return response.send(JSON.stringify({
            accessToken: data.body.access_token,
            refreshToken: data.body.refresh_token,
            expiresIn: data.body.expires_in,
        }));
    }).catch(() => {
        response.sendStatus(400)
    })
})

app.get("/refresh", async (request, response) => {
    spotifyApi.refreshAccessToken().then(data => {
        // save access token
        spotifyApi.setAccessToken(data.body.access_token);

        // show token in browser
        return response.send(JSON.stringify({
            accessToken: data.body.access_token,
            expiresIn: data.body.expires_in,
        }));
    }).catch(() => {
        response.sendStatus(400)
    })
})

app.listen(PORT, () => {
    console.log(`Listening on :${PORT}`)
})

Install dependencies

npm install spotify-web-api-node express cors

Run it

node demo.js

Log in

http://localhost:3000/login

It will display an access token and a refresh token.

Get New Access Token by refreshing the token API

http://localhost:3000/refresh

Demo Result

Reference

Spotify Web API Node