To view the value in the popup, we must reference it in the expressionInfos property of the PopupTemplate's constructor and assign it a name and a title. Bring in the services of an application developer ArcGIS Arcade has a simple scripting syntax that enables you to manipulate your existing data to generate new information based on it. In this case, we are creating a visualization for a FeatureLayer representing U.S. counties. ArcGIS Arcade expression templates for all supported profiles in the ArcGIS platform. I got the book "GIS guidebook: writing arcade expression for ArcGIS Pro, by David W. Allen". First, write the expression in a