N/error Module
UserEventError.recordId
Property Description: Internal ID of the submitted record that triggered the script. This property only holds a value when the error is thrown by an afterSubmit user event script.
Type: string (read-only)
Supported Script Types: User event scripts For more information, see SuiteScript 2.0 User Event Script Type.
Module: N/error Module
Since: 2015.2
Search NetSuite - https://system.netsuite.com/app/help/helpcenter.nl?search=UserEventError.recordId

// Code Example 1

//Add additional code

//...

var UEcustom_error = error.create({

    name: 'MY_ERROR_CODE',

    message: 'my custom UserEventError details',

    notifyOff: false

});

log.debug("Submitted Record ID: " + UEcustom_error.recordId); // recordId is set by the system

                                                             // 'Submitted Record ID: ' followed by the recordId will be logged

//...

//Add additional code



//SOURCE: https://system.netsuite.com/app/help/helpcenter.nl?fid=section_4243803775.html