Merge pull request #1 from UMAprotocol/pablo/fix-clean-object

fix: cleanobject function

index.js

@@ -92,7 +92,7 @@ function _cleanObject(obj) {
       cleanedArray.push(_cleanObject(elt));
     }
     return cleanedArray;
-  } else if (typeof obj === "object") {
+  } else if (typeof obj === "object" && obj !== null) {
 
     // Remove all of the array-style keys, and clean the values for the non array-style keys.
     const cleanedObject = {};