Input returned by PayPal Checkout causes JSON error and causes conflicts.

[ryanr14]

Describe the bug

Hi there, this comes from the WordPress.org forums for this plugin. I was curious what your thoughts would be for this.

WS optin nonce cause Paypal Checkout to fail.

I have an issue with the optin on the checkout page for Paypal only (Stripe works) where the hidden input field with a nonce added by Sendinblue causes the following error with Paypal checkout due to malformed Json. The response of the xhr call via Paypal indeed returns the following raw response:

<input type="hidden" class="ws_opt_in_nonce" name="ws_opt_in_nonce" value= "91eed72c0a"> {"success":true,"data":{"token":"EC-95612932HX675794C"}}

As you can see the input is returned by Paypal causing a malformed json error resulting the following error:

create_order_error {err: "SyntaxError: Unexpected token < in JSON at positio…bility,messages&commit=true&currency=EUR:2:128921", timestamp: "1625481094169", referer: "www.paypal.com", sdkCorrelationID: "a082f9f50c502", sessionID: "uid_1dd075158a_mta6mze6mdq", …}

This occurs despite the response returning “success”.

It has to do with the way form inputs are serialized by PayPal. Any ideas on how to fix? The plugin I am using is Sendinblue Marketing. It may be because the hidden field nonce is appended to the the top of the form.

To reproduce

1. Install PayPal Checkout and Sendinblue plugin.
2. Attempt to cheeckout
3. See error