Fixed tests for length and maxLength

app/node-app/arraymap-beacon/v0.3/beacon-query.js

@@ -70,14 +70,14 @@ function checkPreconditions(params) {
         };
     }
 
-    if (!Number(params.length)) {
+    if (params.length && !Number(params.length)) {
         return {
             hasError: true,
             msg: "min. length not a number"
         };
     }
 
-    if (!Number(params.maxLength)) {
+    if (params.maxLength && !Number(params.maxLength)) {
         return {
             hasError: true,
             msg: "max length not a number"