handlign timeout with Ajax call

I am not a JS guy (can write some basic stuff), I am working on integrating our Payment API with the front end, as part of the process, we want to trigger a timeout in case my back-end Payment API is not responding within a given timeframe. Here is the JS code which interacting with the Payment API.

performAuthorizePaymentRequest: function (payment) {
        return new Promise(function (resolve, reject) {
            $.ajax({
                type: 'POST',
                url: encodedContextPath + '/checkout/authorise_order',
                data: JSON.stringify(payment),
                dataType: 'json',
                contentType: 'application/json',
                success: resolve,
                error: reject,
                always: function () {
                     pageSpinner.end() 
                },
                timeout: 30000 /* call this.session.completePayment() within 30 seconds or the payment is cancelled */
            });
       });
    }

This seems to be working fine, however I have seen the following issue.

1. In case m backed API throws any error, the code is still waiting for the timeout.
2. Even for success cases, the js is waiting for timeout before showing success message.

Is there a way to handle this? Let me know in case I am doing something wrong here.

Note: This code will only execute of Safari, for other browser this is not available

from handlign timeout with Ajax call