bad_script_include_getPropertyList.js

// This is a gist to show how NOT to write a Service Now Script Include to return an array with 
// the results of a query
// As an example, I use the sys_properties table, but of course, any table will do (AKA: not work)

var Toolbox_Functions = Class.create();
Toolbox_Functions.prototype = Object.extendsObject(AbstractAjaxProcessor, {
	
		getPropertyList: function (prefix)
	{
		// 06.11.2017 - Return a list of System Properties whose name starts with prefix
		try {
			var arr = []; 

			var property_gr = new GlideRecord('sys_properties');
			property_gr.addQuery('name', 'STARTSWITH', prefix);
			
			property_gr.query();

			while (property_gr.next())
			{
				// Push new value onto array.
				// THIS IS THE CRITICAL LINE (WRONG!)
				arr.push(property_gr.name);
			}

			return arr;
		} 
		catch(err) 
		{
			gs.eventQueue("script.error", "", "ERROR: PSI_Toolbox_Functions.getPropertyList", err + " in line:" + err.lineNumber);
		}
	}
};
																									 

If you run this, you will be surprised.
As an example, I created these 3 properties:

• sc.firewall.notify.1
• sc.firewall.notify.2
• sc.firewall.notify.3

var Toolbox = new Toolbox_Functions()

var res= Toolbox.getPropertyList("sc.firewall.notify.")
gs.print(res);

[0:00:00.002] Script completed in scope global: script
*** Script: sc.firewall.notify.3,sc.firewall.notify.3,sc.firewall.notify.3

Whoa what's that?
The problem is that property_gr.name (line 23) contains an object reference and it will always point to the last element read (that is why we get the third entry three times)