diff --git a/src/Category.hs b/src/Category.hs
index c20175fb3..980ef002a 100644
--- a/src/Category.hs
+++ b/src/Category.hs
@@ -76,6 +76,8 @@ data Category
   | Case
   -- | An expression with an operator.
   | Operator
+  -- | An comma operator expression
+  | CommaOperator
   -- | An object/dictionary/hash literal.
   | Object
   -- | A throw statement.
diff --git a/src/DiffSummary.hs b/src/DiffSummary.hs
index 957d408f0..d9804a821 100644
--- a/src/DiffSummary.hs
+++ b/src/DiffSummary.hs
@@ -57,7 +57,7 @@ summaries (Replace i1 i2) = zipWith (\a b -> "Replaced" <+> "the" <+> a <+> "wit
 
 toLeafInfos :: DiffInfo -> [Doc]
 toLeafInfos LeafInfo{..} = pure $ squotes (toDoc termName) <+> (toDoc categoryName)
-toLeafInfos BranchInfo{..} = pretty <$> branches
+toLeafInfos BranchInfo{..} = toLeafInfos =<< branches
 toLeafInfos err@ErrorInfo{} = pure $ pretty err
 
 toTermName :: (HasCategory leaf, HasField fields Category, HasField fields Range) => Source Char -> Term leaf (Record fields) -> Text
@@ -214,6 +214,7 @@ instance HasCategory Category where
     C.Class -> "class"
     C.Method -> "method"
     C.If -> "if statement"
+    C.CommaOperator -> "comma operator"
 
 instance (HasCategory leaf, HasField fields Category) => HasCategory (Term leaf (Record fields)) where
   toCategoryName = toCategoryName . category . extract
diff --git a/src/Parser.hs b/src/Parser.hs
index 297516fcf..f59b65e09 100644
--- a/src/Parser.hs
+++ b/src/Parser.hs
@@ -55,6 +55,9 @@ termConstructor source sourceSpan info = fmap cofree . construct
       (base:element:[]) -> withDefaultInfo $ S.SubscriptAccess base element
       _ -> errorWith children
     construct children | isOperator (category info) = withDefaultInfo $ S.Operator children
+    construct children | CommaOperator == category info = withDefaultInfo $ case children of
+      [child, rest] | S.Indexed cs <- unwrap rest -> S.Indexed $ child : toList cs
+      _ -> S.Indexed children
     construct children | Function == category info = case children of
       (body:[]) -> withDefaultInfo $ S.Function Nothing Nothing body
       (params:body:[]) | (info :< _) <- runCofree params, Params == category info ->
diff --git a/src/Renderer.hs b/src/Renderer.hs
index fbbfca8c3..0c537d657 100644
--- a/src/Renderer.hs
+++ b/src/Renderer.hs
@@ -24,10 +24,12 @@ concatOutputs l = T.intercalate "\n" (toText <$> l)
 toSeries :: Output -> Series
 toSeries (JSONOutput series) = series
 toSeries (SummaryOutput series) = series
+toSeries _ = mempty
 
 toText :: Output -> Text
 toText (SplitOutput text) = text
 toText (PatchOutput text) = text
+toText _ = mempty
 
 
 -- | The available types of diff rendering.
diff --git a/src/TreeSitter.hs b/src/TreeSitter.hs
index 722f72202..d76c460eb 100644
--- a/src/TreeSitter.hs
+++ b/src/TreeSitter.hs
@@ -42,7 +42,7 @@ categoriesForLanguage language name = case (language, name) of
   (JavaScript, "bool_op") -> BinaryOperator -- boolean operator, e.g. ||, &&.
   (JavaScript, "bitwise_op") -> BinaryOperator -- bitwise operator, e.g. ^, &, etc.
   (JavaScript, "rel_op") -> BinaryOperator -- relational operator, e.g. >, <, <=, >=, ==, !=.
-  (JavaScript, "comma_op") -> Operator -- comma operator, e.g. expr1, expr2.
+  (JavaScript, "comma_op") -> CommaOperator -- comma operator, e.g. expr1, expr2.
   (JavaScript, "delete_op") -> Operator -- delete operator, e.g. delete x[2].
   (JavaScript, "type_op") -> Operator -- type operator, e.g. typeof Object.
   (JavaScript, "void_op") -> Operator -- void operator, e.g. void 2.
diff --git a/test/repos/js-test b/test/repos/js-test
index 3af143b53..45875c177 160000
--- a/test/repos/js-test
+++ b/test/repos/js-test
@@ -1 +1 @@
-Subproject commit 3af143b53c8f9a2a6761d8e9ea91d47982cc3bc0
+Subproject commit 45875c177feba7e9c25f780669e6719c59441a42