netsuite User Event: Before and After Submit events After Submit: Determine whether a field was changed

Example

After the record gets stored in the database, we want to inspect what was changed on the record. We'll do this inspection by comparing values between the old and new record instances.

// 1.0, Revealing Module pattern
var myNamespace = myNamespace || {};
myNamespace.example = (function () {

    /**
     * User Event 1.0 example detailing usage of the Submit events
     *
     * @appliedtorecord employee
     */
    var exports = {};

    function afterSubmit(type) {
        notifySupervisor();
    }

    function notifySupervisor() {
        // Old and New record instances are retrieved from global functions
        var employee = nlapiGetNewRecord();
        var prevEmployee = nlapiGetOldRecord();

        // If Employee Status didn't change, there's nothing to do
        if (!didStatusChange(employee, prevEmployee)) {
            return;
        }

        // Otherwise, continue with business logic...
    }

    function didStatusChange(employee, prevEmployee) {
        var status = employee.getFieldValue("employeestatus");
        var prevStatus = prevEmployee.getFieldValue("employeestatus");

        /* !! Caution !!
         * Empty fields from the Old record come back as `null`
         * Empty fields from the New record come back as an empty String
         * This means  you cannot simply compare the old and new
         */
        return ((prevStatus || status) && (status !== prevStatus));
    }

    exports.afterSubmit = afterSubmit;
    return exports;
})();

// 2.0
define(["N/runtime"], function (runtime) {

    /**
     * User Event 2.0 example detailing usage of the Submit events
     *
     * @NApiVersion 2.x
     * @NModuleScope SameAccount
     * @NScriptType UserEventScript
     * @appliedtorecord employee
     */
    var exports = {};

    function afterSubmit(scriptContext) {
        notifySupervisor(scriptContext);
    }

    function notifySupervisor(scriptContext) {
        // Old and New records are simply properties on scriptContext
        var employee = scriptContext.newRecord;
        var prevEmployee = scriptContext.oldRecord;

        // If Employee Status didn't change, there's nothing to do
        if (!didStatusChange(employee, prevEmployee)) {
            return;
        }

        // Otherwise, continue with business logic...
    }

    function didStatusChange(employee, prevEmployee) {
        var status = employee.getValue({"fieldId" : "employeestatus"});
        var prevStatus = prevEmployee.getValue({"fieldId" : "employeestatus"});

        /* !! Caution !!
         * Empty fields from the Old record come back as `null`
         * Empty fields from the New record come back as an empty String
         * This means  you cannot simply compare the old and new
         */
        return ((prevStatus || status) && (status !== prevStatus));
    }

    exports.afterSubmit = afterSubmit;
    return exports;
});

Be very cautious when comparing values between old and new records. Empty fields from the old record are returned as null, while empty fields from the new record are returned as an empty String. This means you cannot simply compare the old with the new, or you will get false positives. Any logic you write must handle the case where one is null and one is an empty String appropriately.