What Stripe.applePay.checkAvailability actually does

stripe.js

Stripe.applePay.checkAvailability = function (callback) {
  if (location.protocol === 'https:') {
    var canMakePayments = window.ApplePaySession && ApplePaySession.canMakePayments()

    if (/^pk_test_/.test(Stripe.key || Stripe.publishableKey)) {
      callback(canMakePayments)
    } else if (canMakePayments) {
      var merchantId = "merchant." + window.location.hostname + ".stripe"
      ApplePaySession.canMakePaymentsWithActiveCard(merchantId).then(callback)
    } else {
      callback(false)
    }
  } else {
    console.warn("To use Apple Pay, you must serve your page over HTTPS.")
    callback(false)
  }
}

Thanks for this.

They should change line 6 to be called asynchronously, maybe setTimeout(callback(canMakePayments), 0).

I was calling this function to check if apple pay is supported before starting the apple pay session. Since this function is synchronous in test mode, we saw the issue about having to start apple pay session directly from user action only after it was deployed to production.

It was a silly mistake but this function could have warned me earlier.