Discord Ouath2 Access Token 'Grant type None is not supported'

Question

Im trying to make a login system with discord for my website that is made with express. I have made a function to get an access token so that I can use that function in the route.

Im trying to get an access token from: https://discord.com/api/oauth2/token

Here is my code:

    async GetToken(code) {
        let access_token;
        const payload = {
            'client_id': client_id,
            'client_secret': client_secret,
            'grant_type': 'authorization_code',
            'code': code,
            'redirect_uri': redirect_uri,
            'scope': scope,
        };
        const config = {
            headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
        };
        fetch(discord_token_url, {
            method: 'post',
            body: payload,
            headers: config.headers,
        }).then(response => response.json()).then(json => console.log(json)).catch(err => console.log(err));
        return access_token;
    },

And here's the err I get:

{
  error: 'unsupported_grant_type',
  error_description: 'Grant type None is not supported'
}

As you can see I've given the correct grant type yet I get this error.

Answer 1

Forgot to update to add the solution and saw a lot of people looking at this so here's the solution (thanks to @Kira): You have to use URLSearchParams

// Modules
const fetch = require('node-fetch');
const { url } = require('inspector');
const { URLSearchParams } = require('url');

// Add the parameters
const params = new URLSearchParams();
params.append('client_id', client_id);
params.append('client_secret', client_secret);
params.append('grant_type', 'authorization_code');
params.append('code', code);
params.append('redirect_uri', redirect_uri);
params.append('scope', scope);

// Send the request
fetch('https://discord.com/api/oauth2/token', {
  method: 'post',
  body: params,
  headers: { 'Content-Type': 'application/x-www-form-urlencoded', 'Accept': 'application/json' },
}).then(r => r.json()).then(Response => {
  // Handle it...
  handle()
});