You could add something like the following to the mainplugin.js file. It will be called after the "Ok" button is clicked in the property editor Dialog. Note that if the property editor does not display a dialog, it will be called as each character is typed in the editor.
// access the work item properties after a property has been updated
aspect.after(WorkItemPropertiesPane.prototype, "validate", function(focus, onEditStatus, onSaveStatus) {
console.log("Enter - after WorkItemPropertiesPane::validate");
if (this._workItem && this._workItem.attributes) {
var numAttributes = this._workItem.attributes.length;
}
console.log("Exit - after WorkItemPropertiesPane::validate");
});
#IBMContentNavigator(ICN)#Support#SupportMigration