Add custom JSONEncoder for subscribe_trigger WS endpoint (#48664)

homeassistant/helpers/json.py

@@ -1,5 +1,5 @@
 """Helpers to help with encoding Home Assistant objects in JSON."""
-from datetime import datetime
+from datetime import datetime, timedelta
 import json
 from typing import Any
 
@@ -20,3 +20,19 @@ class JSONEncoder(json.JSONEncoder):
             return o.as_dict()
 
         return json.JSONEncoder.default(self, o)
+
+
+class ExtendedJSONEncoder(JSONEncoder):
+    """JSONEncoder that supports Home Assistant objects and falls back to repr(o)."""
+
+    def default(self, o: Any) -> Any:
+        """Convert certain objects.
+
+        Fall back to repr(o).
+        """
+        if isinstance(o, timedelta):
+            return {"__type": str(type(o)), "total_seconds": o.total_seconds()}
+        try:
+            return super().default(o)
+        except TypeError:
+            return {"__type": str(type(o)), "repr": repr(o)}