server.js

const express = require("express");
require('dotenv').config()
const app = express();
var cors = require("cors");

// This is a public sample test API key.
// Don’t submit any personally identifiable information in requests made with this key.
// Sign in to see your own test API key embedded in code samples.
const stripe = require("stripe")(
    process.env.SECRET_KEY
);

app.use(express.static("public"));
app.use(express.json());
app.use(
    cors({
        origin: ["http://localhost:3000"],
    })
);

const YOUR_DOMAIN = process.env.MY_DOMAIN

app.get("/", (req, res) => res.send("Express on Vercel"));


app.post('/create-checkout-session', async (req, res) => {
  const session = await stripe.checkout.sessions.create({
    line_items: [
      {
        // Provide the exact Price ID (for example, pr_1234) of the product you want to sell
        price: 'price_1PHbifJyDRgsgtRAFeooOdIZ',
        quantity: 1,
      },
    ],
    mode: 'payment',
    success_url: `${YOUR_DOMAIN}?success=true`,
    cancel_url: `${YOUR_DOMAIN}?canceled=true`,
  });

  res.redirect(303, session.url);
});

// app.listen(4242, () => console.log('Running on port 4242'));


const calculateOrderAmount = (items) => {
  // Replace this constant with a calculation of the order's amount
  // Calculate the order total on the server to prevent
  // people from directly manipulating the amount on the client
  return 1400;
};

app.post("/create-payment-intent", async (req, res) => {
    const { items } = req.body;

    // Create a PaymentIntent with the order amount and currency
    const paymentIntent = await stripe.paymentIntents.create({
        amount: calculateOrderAmount(items),
        currency: "usd",
        // In the latest version of the API, specifying the `automatic_payment_methods` parameter is optional because Stripe enables its functionality by default.
        automatic_payment_methods: {
            enabled: true,
        },
    });

    res.send({
        clientSecret: paymentIntent.client_secret,
    });
});

app.listen(4242, () => console.log("Node server listening on port 4242!"));

module.exports = app;