const code = ** my authorization code ** ;
const CLIENT_ID = ** my client id ** ;
const CLIENT_SECRET = ** my client secret ** ;
const creds = btoa(`${CLIENT_ID}:${CLIENT_SECRET}`);
fetch(`https://discordapp.com/api/oauth2/token`, {
        method: "POST",
        headers: {
            Authorization: `Basic ${creds}`,
        },
        body: JSON.stringify({
            grant_type: 'authorization_code',
            code: code,
            redirect_uri: redirect
        }),
    })
    .then((res) => res.json())
    .then((body) => console.log(body));