fix export of visible false

src/json-utils_1.1.js

@@ -113,8 +113,8 @@ function getAttributes(entity) {
     elemObj['components'] = {};
     for (const componentName in entityComponents) {
       const modifiedProperty = getModifiedProperty(entity, componentName);
-      if (modifiedProperty) {
-        if (isEmpty(modifiedProperty)) {
+      if (modifiedProperty !== null) {
+        if (isEmptyObject(modifiedProperty)) {
           elemObj['components'][componentName] = '';
         } else {
           elemObj['components'][componentName] = toPropString(modifiedProperty);
@@ -168,8 +168,13 @@ function isSingleProperty(schema) {
   return AFRAME.schema.isSingleProperty(schema);
 }
 
-function isEmpty(object) {
-  return Object.keys(object).length === 0;
+function isEmptyObject(object) {
+  return (
+    typeof object === 'object' &&
+    !Array.isArray(object) &&
+    object !== null &&
+    Object.keys(object).length === 0
+  );
 }
 
 // a list of component:value pairs to exclude from the JSON string.
@@ -201,7 +206,7 @@ function filterJSONstreet(streetJSON) {
         compAttributes = AFRAME.utils.styleParser.parse(value);
         const removeVal = removeProps[removeKey];
         // check for deleting component's attribute
-        if (typeof removeVal === 'object' && !isEmpty(removeVal)) {
+        if (!isEmptyObject(removeVal)) {
           // remove attribute in component
           const attrNames = Object.keys(removeVal);
           for (var attrName of attrNames) {