stripe-react-serverless-31.ts

class StripeManager {
  ...

  public static async createSubscription(customerID: string, paymentMethodID: string) {
    const request = await fetch('https://your-endpoint/stripe/create-subscription', {
      method: 'POST',
      body: JSON.stringify({
        customerID,
        paymentMethodID,
      }),
    });

    const subscription = await request.json() as IStripeSubscription;
    if (subscription.status !== 'active') {
      throw Error('Unable to upgrade. Please try again');
    }

    if (subscription.latest_invoice.payment_intent.status === 'requires_payment_method') {
      throw Error('You credit card was declined. Please try again with another card.');
    }

    // Update your user in DB to store the subscriptionID and enable paid plan
    // updateUserInDB() is *your* implementation of updating a user in the DB
    updateUserInDB({
      paymentMethodID,
      hasPaidPlan: true,
      subscriptionID: subscription.id,
    });

    return subscription;
  }

  ...
}