Introduction

const isDespia = navigator.userAgent.toLowerCase().includes('despia')

window.stripeEvent = function (event) {
    if (event.method !== 'paymentSheet') return
    if (event.status === 'completed') {
        // Confirm via your backend webhook before fulfilling the order.
    }
}

async function pay() {
    const res = await fetch('/api/create-payment-intent', { method: 'POST' })
    const { publishable_key, client_secret } = await res.json()

    if (isDespia) {
        despia(`stripe://payment?publishable_key=${publishable_key}&payment_intent_client_secret=${client_secret}`)
    }
}

// Your server endpoint, e.g. /api/create-payment-intent
const stripe = require('stripe')(process.env.STRIPE_SECRET_KEY)

app.post('/api/create-payment-intent', async (req, res) => {
    const intent = await stripe.paymentIntents.create({
        amount: 1999,
        currency: 'usd',
        automatic_payment_methods: { enabled: true }
    })

    res.json({
        publishable_key: process.env.STRIPE_PUBLISHABLE_KEY,
        client_secret:   intent.client_secret
    })
})

if (isDespia) {
    despia(`stripe://payment?publishable_key=${publishable_key}&payment_intent_client_secret=${client_secret}&customer_id=${customer_id}&ephemeral_key_secret=${ephemeral_key_secret}`)
}

// Your webhook endpoint, e.g. /api/stripe/webhook
app.post('/api/stripe/webhook', express.raw({ type: 'application/json' }), (req, res) => {
    const event = stripe.webhooks.constructEvent(
        req.body,
        req.headers['stripe-signature'],
        process.env.STRIPE_WEBHOOK_SECRET
    )

    if (event.type === 'payment_intent.succeeded') {
        const intent = event.data.object
        // Unlock the order keyed off intent.id or intent.metadata.
    }

    res.json({ received: true })
})

window.stripeEvent = function (event) {
    if (event.method !== 'paymentSheet') return
    if (event.status === 'completed') {
        fetch('/api/confirm-payment', { method: 'POST' })
    }
}