* Add helper function for checking objects for required properties

Das_Schwarze_Auge_4-1/dsa4_1_character_sheet_roll20.html

@@ -16813,6 +16813,25 @@ function DSAsane (value, type) {
 	return !errors;
 }
 
+/*
+	Property Checker
+	Checks whether properties (given in an array of strings) are available in an object.
+	Does not check whether the array contains strings only.
+	Returns an object with the error count (missing properties) and a string array of missing properties.
+*/
+function checkRequiredProperties(properties, values) {
+	var errors = 0;
+	var missing = [];
+
+	for (req of properties) {
+		if (!values.hasOwnProperty(req)) {
+			errors += 1;
+			missing.push(req);
+		}
+	}
+	return { "errors": errors, "missing": missing.toString() };
+}
+
 // Berechne BE-Basis aus dem gesamten Rüstungs BE und der BE durch Last
 on("change:Ges_BE change:BE_Last", function(eventInfo) {
     getAttrs(["Ges_BE", "BE_Last"], function(values) {