Synchronous Stripe PaymentIntents Flow

client.js

export async function api(method, path = '', { body = {}, headers = {} } = {}) {
	/* global ORIGIN */
	let opts = { method, headers }
	if(method == 'POST') {
		opts.body = JSON.stringify(body)
	}
	let res = await fetch((process.browser ? '' : ORIGIN) + '/api/'+path, opts)
	res.text = await res.text()
	try {
		res.json = JSON.parse(res.text)
	} catch(e) {
		res.json = {}
	}

	if(res.json.errors) {
		res.errors = res.json.errors
	} else if(!res.ok) {
		res.errors = [{ message: res.text }]
	} else {
		res.errors = []
	}

	return res
}

async function pay() {
  let payment_method = await stripe.createPaymentMethod('card', card, {
    billing_details: billing
  })

  if (payment_method.error) {
    errs = [payment_method.error]
    spinning = false
  } else {
    // step 2
    handleServerResponse(await api('POST', 'pay', { body: { 
      payment_method_id: payment_method.paymentMethod.id 
    } }))
  }
}

async function handleServerResponse(response) {
  let { json, status, text, errors } = response

  if(errors.length) {
    errs = errors
  }
  else if (json.requires_action) {
    // step 3
    let action = await stripe.handleCardAction(json.payment_intent_client_secret)

    if (action.error) {
      errs = [action.error]
    } else {
      handleServerResponse(await api('POST', 'pay', { body: { 
        payment_intent_id: json.paymentIntent.id 
      } }))
    }
  } else {
    dispatch('success')
  }
}

server.js

// assume an express-like context with req, res, etc

let send = require('@polka/send-type')

if (req.body.payment_method_id) {
  intent = await stripe.paymentIntents.create({
    payment_method: req.body.payment_method_id,
    amount: rate.total,
    currency: 'usd',
    confirmation_method: 'manual',
    confirm: true
  })
} else if (req.body.payment_intent_id) {
  intent = await stripe.paymentIntents.confirm(req.body.payment_intent_id)
} else {
  throw('Please provide stripe payment method or intent')
}

if (intent.status === 'requires_action' && intent.next_action.type === 'use_stripe_sdk') {
  return send(res, 200, {
    requires_action: true,
    payment_intent_client_secret: intent.client_secret
  })
}

if(intent.status !== 'succeeded') {
  return send(res, 500, 'Invalid PaymentIntent status')
}