ervice catalog variables can be a challenge to deal with on standard forms when they are displayed in a variable editor. I’ve written before about different ways that you can solve one of these challenges…making the variables read only, so that they can’t be modified after the initial submission through the service catalog interface. Another common problem I’ve seen is that you can end up with a lot of variables that end up empty in the variable editor on your request item or task because they were optional or hidden on the front-end catalog form. If the variables are empty and you aren’t going to have users interact with them on the standard forms then there isn’t much use in having these variables show up at all in the variable editor.

Until now there really hasn’t been a good way to deal with this issue because of the challenges of dealing with so many different variable types in client-side JavaScript. A couple of days ago one of my colleagues, Jacob Kimball, suggested to me that we might be able to overcome this issue by using a ‘display’ business rule to collect the blank variable information at the server and then pass those variable names to the client. So, you can thank Jacob Kimball for the brilliance of this solution. I’m just spreading the love. 🙂

As explained above, the key to making this work is a ‘display’ business rule. The business rule runs before the display of any record in the table (tasks in this case) and queries the ‘sc_item_option_mtom’ and ‘question_answer’ tables to collect any variable names for empty variables. Then it passes this information in the ‘g_scratchpad’ object to the client to hide the variables on the form.

Here is how you could set up the business rule. The script is designed to hide any empty variables for any task records whether they are generated from a record producer or as a catalog item.

‘Hide Empty Variables’ Business Rule
Name: Hide Empty Variables
Table: Task
When: display
Condition: !RP.isPopup()

//Initialize the scratchpad variable
g_scratchpad.emptyVars = '';

//Check to see if a variable pool exists
var count = 0;
for(vars in current.variable_pool){

//If a variable pool exists then collect empty variable names
if(count > 0){
   var emptyVars = [];
   var table = current.getTableName();
   //Query for the empty variables for this record
   //Catalog item and task variables pull from 'sc_item_option_mtom' table
   if(table == 'sc_req_item' || table == 'sc_task'){
      var itemVars = new GlideRecord('sc_item_option_mtom');
      if(table == 'sc_req_item'){
         itemVars.addQuery('request_item', current.sys_id);
      if(table == 'sc_task'){
         itemVars.addQuery('request_item', current.request_item.sys_id);
      //Exclude Label and Container variables
      itemVars.addQuery('sc_item_option.item_option_new.type', '!=', 11);
      itemVars.addQuery('sc_item_option.item_option_new.type', '!=', 19);
      itemVars.addQuery('sc_item_option.item_option_new.type', '!=', 20);
         //Add variable names to the emptyVars array
      //All other variables pulled from 'question_answer' table
      var producerVars = new GlideRecord('question_answer');
      producerVars.addQuery('table_sys_id', current.sys_id);
      //Exclude Label and Container variables
      producerVars.addQuery('question.type', '!=', 11);
      producerVars.addQuery('question.type', '!=', 19);
      producerVars.addQuery('question.type', '!=', 20);
         //Add variable names to the emptyVars array

   //Store the result in the scratchpad
   g_scratchpad.emptyVars = emptyVars.join();

Once you’ve got the empty variable names collected all you have to do is set up a client script to grab the ‘g_scratchpad’ variable, split out any empty variable names, and hide each one. The client script is pretty simple since the heavy lifting is being done in the business rule. Just make sure that you check the ‘Inherited’ checkbox if you decide to set this up on the task table!

‘Hide Empty Variables’ Client Script
Name: Hide Empty Variables
Type: OnLoad
Table: Task
Inherited: True

function onLoad() {
   //Hide all empty variables using the scratchpad object passed from 'Hide Empty Variables' business rule
   if(g_scratchpad.emptyVars != ''){
      var emptyVars = g_scratchpad.emptyVars.split(',');
      for(i = 0; i < emptyVars.length; i++){
         g_form.setDisplay('variables.' + emptyVars[i], false);