const body = {
    client_id: "my_id",
    client_secret: "my_secret",
    grant_type: "client_credentials"
}
fetch('https://id.twitch.tv/oauth2/token', {
    method: 'post',
    headers: {
        'Accept': 'application/json, text/plain, */*',
        'Content-Type': 'application/json'
    },
    body: JSON.stringify(body)
})
.then(function (response) {
    return response.json();
})
.then(function (result) {
    console.log(result);
})
.catch (function (error) {
    console.log('Request failed', error);
});