valueProcess.js

import("system.vars");
import("system.result");
import("Keyword_lib");

var histMedium;
histMedium = vars.get("$field.CATEGORY");
if (histMedium){
    result.string(vars.get("$field.SUBJECT") + " (" + LegacyKeywordUtils.getViewValue("ACTIVITY.CATEGORY", histMedium) + ")");
}