From e2ee3f3cfc5663db9e2693f90920d04612975178 Mon Sep 17 00:00:00 2001
From: Brock <jbrockmendel@gmail.com>
Date: Wed, 14 Jun 2023 16:44:36 -0700
Subject: [PATCH 1/2] REF: move values_for_json to EA

---
 pandas/core/arrays/base.py         |  4 ++++
 pandas/core/arrays/datetimelike.py |  6 ++++++
 pandas/core/internals/blocks.py    | 16 ----------------
 pandas/core/internals/managers.py  |  2 +-
 4 files changed, 11 insertions(+), 17 deletions(-)

diff --git a/pandas/core/arrays/base.py b/pandas/core/arrays/base.py
index 27eb7994d3ccb..554e4a3b385b4 100644
--- a/pandas/core/arrays/base.py
+++ b/pandas/core/arrays/base.py
@@ -1443,6 +1443,10 @@ def _reduce(self, name: str, *, skipna: bool = True, **kwargs):
     # Non-Optimized Default Methods; in the case of the private methods here,
     #  these are not guaranteed to be stable across pandas versions.
 
+    def _values_for_json(self) -> np.ndarray:
+        # TODO: document!
+        return np.asarray(self)
+
     def _hash_pandas_object(
         self, *, encoding: str, hash_key: str, categorize: bool
     ) -> npt.NDArray[np.uint64]:
diff --git a/pandas/core/arrays/datetimelike.py b/pandas/core/arrays/datetimelike.py
index ea085b3d1f6ab..2c53a605185ec 100644
--- a/pandas/core/arrays/datetimelike.py
+++ b/pandas/core/arrays/datetimelike.py
@@ -2186,6 +2186,12 @@ def _with_freq(self, freq) -> Self:
     # --------------------------------------------------------------
     # ExtensionArray Interface
 
+    def _values_for_json(self) -> np.ndarray:
+        # Small performance bump vs the base class which calls np.asarray(self)
+        if isinstance(self.dtype, np.dtype):
+            return self._ndarray
+        return super()._values_for_json()
+
     def factorize(
         self,
         use_na_sentinel: bool = True,
diff --git a/pandas/core/internals/blocks.py b/pandas/core/internals/blocks.py
index 981e29df2c323..eaeaa99fc6370 100644
--- a/pandas/core/internals/blocks.py
+++ b/pandas/core/internals/blocks.py
@@ -1602,9 +1602,6 @@ def get_values(self, dtype: DtypeObj | None = None) -> np.ndarray:
         """
         raise AbstractMethodError(self)
 
-    def values_for_json(self) -> np.ndarray:
-        raise AbstractMethodError(self)
-
 
 class EABackedBlock(Block):
     """
@@ -1835,9 +1832,6 @@ def get_values(self, dtype: DtypeObj | None = None) -> np.ndarray:
         # TODO(EA2D): reshape not needed with 2D EAs
         return np.asarray(values).reshape(self.shape)
 
-    def values_for_json(self) -> np.ndarray:
-        return np.asarray(self.values)
-
     def interpolate(
         self,
         *,
@@ -2145,9 +2139,6 @@ def get_values(self, dtype: DtypeObj | None = None) -> np.ndarray:
             return self.values.astype(_dtype_obj)
         return self.values
 
-    def values_for_json(self) -> np.ndarray:
-        return self.values
-
     @cache_readonly
     def is_numeric(self) -> bool:  # type: ignore[override]
         dtype = self.values.dtype
@@ -2245,9 +2236,6 @@ class DatetimeLikeBlock(NDArrayBackedExtensionBlock):
     is_numeric = False
     values: DatetimeArray | TimedeltaArray
 
-    def values_for_json(self) -> np.ndarray:
-        return self.values._ndarray
-
     def interpolate(
         self,
         *,
@@ -2304,10 +2292,6 @@ class DatetimeTZBlock(DatetimeLikeBlock):
     _validate_ndim = True
     _can_consolidate = False
 
-    # Don't use values_for_json from DatetimeLikeBlock since it is
-    # an invalid optimization here(drop the tz)
-    values_for_json = NDArrayBackedExtensionBlock.values_for_json
-
 
 # -----------------------------------------------------------------
 # Constructor Helpers
diff --git a/pandas/core/internals/managers.py b/pandas/core/internals/managers.py
index 2a7c0536c66a4..b8b490c5bb56e 100644
--- a/pandas/core/internals/managers.py
+++ b/pandas/core/internals/managers.py
@@ -1110,7 +1110,7 @@ def column_arrays(self) -> list[np.ndarray]:
 
         for blk in self.blocks:
             mgr_locs = blk._mgr_locs
-            values = blk.values_for_json()
+            values = blk.array_values._values_for_json()
             if values.ndim == 1:
                 # TODO(EA2D): special casing not needed with 2D EAs
                 result[mgr_locs[0]] = values

From ccdee02abd46db8ecd4949597ef218eb908b576a Mon Sep 17 00:00:00 2001
From: Brock <jbrockmendel@gmail.com>
Date: Fri, 23 Jun 2023 09:58:51 -0700
Subject: [PATCH 2/2] docstring

---
 pandas/core/arrays/base.py | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/pandas/core/arrays/base.py b/pandas/core/arrays/base.py
index 582e85162b33c..56284647ebb3e 100644
--- a/pandas/core/arrays/base.py
+++ b/pandas/core/arrays/base.py
@@ -1449,7 +1449,16 @@ def _reduce(self, name: str, *, skipna: bool = True, **kwargs):
     #  these are not guaranteed to be stable across pandas versions.
 
     def _values_for_json(self) -> np.ndarray:
-        # TODO: document!
+        """
+        Specify how to render our entries in to_json.
+
+        Notes
+        -----
+        The dtype on the returned ndarray is not restricted, but for non-native
+        types that are not specifically handled in objToJSON.c, to_json is
+        liable to raise. In these cases, it may be safer to return an ndarray
+        of strings.
+        """
         return np.asarray(self)
 
     def _hash_pandas_object(