diff --git a/src/plot_api/plot_schema.js b/src/plot_api/plot_schema.js
index 972835dbfb2..c5a55ef34ee 100644
--- a/src/plot_api/plot_schema.js
+++ b/src/plot_api/plot_schema.js
@@ -61,7 +61,7 @@ exports.get = function() {
     return {
         defs: {
             valObjects: Lib.valObjects,
-            metaKeys: UNDERSCORE_ATTRS.concat['description', 'role']
+            metaKeys: UNDERSCORE_ATTRS.concat(['description', 'role'])
         },
 
         traces: traces,
diff --git a/test/jasmine/tests/plotschema_test.js b/test/jasmine/tests/plotschema_test.js
index ec7b4819fe4..eb0983b4857 100644
--- a/test/jasmine/tests/plotschema_test.js
+++ b/test/jasmine/tests/plotschema_test.js
@@ -187,4 +187,11 @@ describe('plot schema', function() {
             expect(attrNames).toContain(k);
         });
     });
+
+    it('should list correct defs', function() {
+        expect(plotSchema.defs.valObjects).toBeDefined();
+
+        expect(plotSchema.defs.metaKeys)
+            .toEqual(['_isSubplotObj', '_isLinkedToArray', '_deprecated', 'description', 'role']);
+    });
 });