Fixed JSONEditor not working without having a schema defined

.gitignore

@@ -1,4 +1,5 @@
 .idea
+.vscode
 build
 downloads
 node_modules

src/js/Node.js

@@ -1998,7 +1998,9 @@ Node.prototype._updateSchema = function () {
   //Locating the schema of the node and checking for any enum type
   if(this.editor && this.editor.options) {
     // find the part of the json schema matching this nodes path
-    this.schema = Node._findSchema(this.editor.options.schema, this.getPath());
+    this.schema = this.editor.options.schema 
+        ? Node._findSchema(this.editor.options.schema, this.getPath())
+        : null;
     if (this.schema) {
       this.enum = Node._findEnum(this.schema);
     }