Added annotations and benchmarks

Author: Chris Bertinato

asv_bench/benchmarks/io/json.py

@@ -66,7 +66,7 @@ class ToJSON(BaseIO):
     fname = "__test__.json"
     params = [
         ["split", "columns", "index", "values", "records"],
-        ["df", "df_date_idx", "df_td_int_ts", "df_int_floats", "df_int_float_str"],
+        ["df", "df_date_idx", "df_td", "df_td_int_ts", "df_int_floats", "df_int_float_str"],
     ]
     param_names = ["orient", "frame"]
 
@@ -81,6 +81,13 @@ def setup(self, orient, frame):
         strings = tm.makeStringIndex(N)
         self.df = DataFrame(np.random.randn(N, ncols), index=np.arange(N))
         self.df_date_idx = DataFrame(np.random.randn(N, ncols), index=index)
+        self.df_td = DataFrame(
+            {
+                "td_1": timedeltas,
+                "td_2": timedeltas
+            },
+            index=index,
+        )
         self.df_td_int_ts = DataFrame(
             {
                 "td_1": timedeltas,

pandas/io/json/_json.py

@@ -174,14 +174,14 @@ class SeriesWriter(Writer):
     def __init__(
         self,
         obj,
-        orient,
-        date_format,
-        double_precision,
-        ensure_ascii,
-        date_unit,
-        index,
-        default_handler=None,
-        indent=0,
+        orient: Optional[str],
+        date_format: str,
+        double_precision: int,
+        ensure_ascii: bool,
+        date_unit: str,
+        index: bool,
+        default_handler: Optional[Callable[[Any], Serializable]] = None,
+        indent: int = 0,
     ):
         super().__init__(
             obj,
@@ -237,14 +237,14 @@ class FrameWriter(Writer):
     def __init__(
         self,
         obj,
-        orient,
-        date_format,
-        double_precision,
-        ensure_ascii,
-        date_unit,
-        index,
-        default_handler=None,
-        indent=0,
+        orient: Optional[str],
+        date_format: str,
+        double_precision: int,
+        ensure_ascii: bool,
+        date_unit: str,
+        index: bool,
+        default_handler: Optional[Callable[[Any], Serializable]] = None,
+        indent: int = 0,
     ):
         super().__init__(
             obj,