json: add support for default encoder

rich/json.py

@@ -1,5 +1,5 @@
 from json import loads, dumps
-from typing import Any
+from typing import Any, Callable, Optional
 
 from .text import Text
 from .highlighter import JSONHighlighter, NullHighlighter
@@ -23,17 +23,26 @@ class JSON:
         self.text.overflow = None
 
     @classmethod
-    def from_data(cls, data: Any, indent: int = 2, highlight: bool = True) -> "JSON":
+    def from_data(
+        cls,
+        data: Any,
+        indent: int = 2,
+        highlight: bool = True,
+        default: Optional[Callable[[Any], Any]] = None,
+    ) -> "JSON":
         """Encodes a JSON object from arbitrary data.
 
+        Args:
+            data (Any): An object that may be encoded in to JSON
+            indent (int, optional): Number of characters to indent by. Defaults to 2.
+            highlight (bool, optional): Enable highlighting. Defaults to True.
+            default (Callable, optional): Optional callable which will be called for objects that cannot be serialized. Defaults to None.
+
         Returns:
-            Args:
-                data (Any): An object that may be encoded in to JSON
-                indent (int, optional): Number of characters to indent by. Defaults to 2.
-                highlight (bool, optional): Enable highlighting. Defaults to True.
+            JSON: New JSON object from the given data.
         """
         json_instance: "JSON" = cls.__new__(cls)
-        json = dumps(data, indent=indent)
+        json = dumps(data, indent=indent, default=default)
         highlighter = JSONHighlighter() if highlight else NullHighlighter()
         json_instance.text = highlighter(json)
         json_instance.text.no_wrap = True

tests/test_json.py

@@ -0,0 +1,8 @@
+from rich.json import JSON
+import datetime
+
+
+def test_print_json_data_with_default():
+    date = datetime.date(2021, 1, 1)
+    json = JSON.from_data({"date": date}, default=lambda d: d.isoformat())
+    assert str(json.text) == '{\n  "date": "2021-01-01"\n}'