diff --git a/src/DiffSummary.hs b/src/DiffSummary.hs
index 887949fb3..500fee238 100644
--- a/src/DiffSummary.hs
+++ b/src/DiffSummary.hs
@@ -59,19 +59,21 @@ toTermName source term = case unwrap term of
   S.Switch expr _ -> toTermName' expr
   S.Ternary expr _ -> toTermName' expr
   S.MathAssignment id _ -> toTermName' id
-  S.Operator syntaxes -> mconcat $ toTermName' <$> syntaxes
+  S.Operator _ -> termNameFromSource term
   S.Object kvs -> "{" <> intercalate ", " (toTermName' <$> kvs) <> "}"
   S.Pair a b -> toTermName' a <> ": " <> toTermName' b
   S.Return expr -> maybe "empty" toTermName' expr
-  S.For exprs _ -> toText $ Source.slice (unionRangesFrom forRange forClauseRanges) source
-    where forRange = characterRange $ extract term
-          forClauseRanges = characterRange . extract <$> exprs
+  S.For exprs _ -> termNameFromChildren term exprs
   S.While expr _ -> toTermName' expr
   S.DoWhile _ expr -> toTermName' expr
   S.Class identifier _ _ -> toTermName' identifier
   S.Method identifier _ _ -> toTermName' identifier
   Comment a -> toCategoryName a
   where toTermName' = toTermName source
+        termNameFromChildren term cs = termNameFromRange (unionRangesFrom (range term) (range <$> cs))
+        termNameFromSource term = termNameFromRange (range term)
+        termNameFromRange range = toText $ Source.slice range source
+        range = characterRange . extract
 
 class HasCategory a where
   toCategoryName :: a -> Text
@@ -213,7 +215,6 @@ termToDiffInfo blob term = case unwrap term of
   -- Currently we cannot express the operator for an operator production from TreeSitter. Eventually we should be able to
   -- use the term name of the operator identifier when we have that production value. Until then, I'm using a placeholder value
   -- to indicate where that value should be when constructing DiffInfos.
-  S.Operator _ -> LeafInfo (toCategoryName term) "x"
   Commented cs leaf -> BranchInfo (termToDiffInfo' <$> cs <> maybeToList leaf) (toCategoryName term) BCommented
   S.Error sourceSpan _ -> ErrorInfo sourceSpan (toCategoryName term)
   _ -> LeafInfo (toCategoryName term) (toTermName' term)
diff --git a/src/Parser.hs b/src/Parser.hs
index 01cf22bfb..2dc79941a 100644
--- a/src/Parser.hs
+++ b/src/Parser.hs
@@ -17,13 +17,9 @@ import SourceSpan
 -- | and aren't pure.
 type Parser fields = SourceBlob -> IO (Term Text (Record fields))
 
--- | Categories that are treated as fixed nodes.
-fixedCategories :: Set.Set Category
-fixedCategories = Set.fromList [ BinaryOperator, Pair ]
-
--- | Should these categories be treated as fixed nodes?
-isFixed :: Category -> Bool
-isFixed = flip Set.member fixedCategories
+-- | Whether a category is an Operator Category
+isOperator :: Category -> Bool
+isOperator = flip Set.member (Set.fromList [ Operator, BinaryOperator ])
 
 -- | Given a function that maps production names to sets of categories, produce
 -- | a Constructor.
@@ -49,7 +45,7 @@ termConstructor source sourceSpan info = cofree . construct
     construct children | SubscriptAccess == category info = case children of
       (base:element:[]) -> withDefaultInfo $ S.SubscriptAccess base element
       _ -> withDefaultInfo $ S.Error sourceSpan children
-    construct children | Operator == category info = withDefaultInfo $ S.Operator children
+    construct children | isOperator (category info) = withDefaultInfo $ S.Operator children
     construct children | Function == category info = case children of
       (body:[]) -> withDefaultInfo $ S.Function Nothing Nothing body
       (params:body:[]) | (info :< _) <- runCofree params, Params == category info ->
@@ -92,7 +88,7 @@ termConstructor source sourceSpan info = cofree . construct
         toTuple child | S.Leaf c <- unwrap child = [cofree (extract child :< S.Comment c)]
         toTuple child = pure child
 
-    construct children | isFixed (category info) = withDefaultInfo $ S.Fixed children
+    construct children | Pair == (category info) = withDefaultInfo $ S.Fixed children
     construct children | C.Error == category info =
       withDefaultInfo $ S.Error sourceSpan children
     construct children | For == (category info), Just (exprs, body) <- unsnoc children =
diff --git a/src/TreeSitter.hs b/src/TreeSitter.hs
index 13b14a8f9..e3e69179b 100644
--- a/src/TreeSitter.hs
+++ b/src/TreeSitter.hs
@@ -30,17 +30,20 @@ treeSitterParser language grammar blob = do
 categoriesForLanguage :: Language -> Text -> Category
 categoriesForLanguage language name = case (language, name) of
   (JavaScript, "object") -> Object
-  (JavaScript, "rel_op") -> BinaryOperator -- relational operator, e.g. >, <, <=, >=, ==, !=
-  (JavaScript, "bool_op") -> BinaryOperator
   (JavaScript, "expression_statement") -> ExpressionStatements
   (JavaScript, "this_expression") -> Identifier
   (JavaScript, "null") -> Identifier
   (JavaScript, "undefined") -> Identifier
   (JavaScript, "arrow_function") -> Function
   (JavaScript, "generator_function") -> Function
-  (JavaScript, "delete_op") -> Operator
-  (JavaScript, "type_op") -> Operator
-  (JavaScript, "void_op") -> Operator
+  (JavaScript, "math_op") -> BinaryOperator -- bitwise operator, e.g. +, -, *, /.
+  (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, "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.
   (JavaScript, "for_in_statement") -> For
   (JavaScript, "for_of_statement") -> For
   (JavaScript, "class")  -> Class