The NOW You Know series, created by ServiceNow developers for ServiceNow developers, aims to provide valuable insights and practical tips. In this blog, we will explore multi-row variable sets (MRVS), which were introduced in the London release. A MRVS makes it easier to collect and manage complex data sets. As a result, the data can be dynamically accessed and manipulated through client-side scripting, but in order to do so, you first have to access it!
Multi-row variable sets (MRVS) are a fairly recent addition to the Service Catalog in ServiceNow, having been introduced in the London release. Unlike a traditional variable set, which is a collection of singular variables, a MRVS allows the population of an arbitrary* number of rows of data, displayed in a table format, with a series of predefined field columns. Some field types, such as list collectors and macros, and other service catalog functionality (such as ‘Map to field’) are not available from a MRVS. See the official documentation for more details: Service Catalog Variable Sets
When implementing a MRVS, you may wish to be able to dynamically access the values entered into the table. This can be accomplished via client-side scripting. In the example below, our hypothetical requirement is to calculate a sum of decimal values stored in separate rows of the set. We’ll accomplish this by using a macro variable, which will input the total value of the desired column into a field of our choosing.
We start by creating a script that can be accessed via a UI element, such as from a UI macro or Service Portal widget. This script will be an onLoad catalog client script in this case. By loading this script with the form, we give the macro an on-click function in order to do the calculation when the button is pressed.
function onLoad() {
//onLoad function can be empty. We will define our function outside of the onLoad context to put it in a scope reachable by the macro button.
}
function calcTotal() {
var mrvs = g_form.getValue("IO:46c07bd31b25041064d6337bcd4bcb26"); //We can access the MRVS values via getValue, using the "IO:" prefix, followed by the MRVS sys_id
var objList = JSON.parse(mrvs); //The MRVS values are captured as a JSON string, which we parse, creating an array
var calculatedAmount = 0;
var tax = parseFloat(g_form.getValue('u_tax'));
var freight = parseFloat(g_form.getValue('u_freight'));
for (var i = 0; i < objList.length; i++) { //Iterate through array to sum values
calculatedAmount += parseFloat(objList[i].dollar_amount);
}
var taxTotal = tax * calculatedAmount;
var rawTotal = calculatedAmount + taxTotal + freight;
var finalTotal = rawTotal.toFixed(2);
g_form.setValue('u_invoice_total', finalTotal);
}
You can now evoke the calcTotal() function from a UI macro (made with Jelly Script, for use on the classic Service Catalog view) or from a widget on the Service Portal.
The final result should look something like this:
A MVRS offers a powerful way to manage and manipulate complex data sets within the existing ServiceNow environment. Using client-side scripting, you can dynamically access and process the data, so you can do more, faster.
*Baseline, you are restricted to a maximum of 50 rows in a MRVS
While the above technical tip has been provided with care and consideration, it’s important to acknowledge that individual circumstances may vary. Always ensure compatibility and feasibility within your specific ServiceNow environment before implementing any suggestions. Additionally, back up your data and proceed with caution when making any changes to your instance or workflows.
As with any change in ServiceNow, make sure you test any changes prior to moving to production.