Fix the rendering of Dict/Struct

src/itables/datatables_format.py

@@ -121,6 +121,7 @@ def datatables_rows(df, count=None, warn_on_unexpected_types=False, pure_json=Fa
             or (x.dtype == pl.UInt64 and (x > JS_MAX_SAFE_INTEGER).any())
             for x in (df[col] for col in df.columns)
         )
+        data = replace_dicts_with_strings(data)
         js = json.dumps(data, cls=generate_encoder(False), allow_nan=not pure_json)
 
     if has_bigints:
@@ -129,6 +130,10 @@ def datatables_rows(df, count=None, warn_on_unexpected_types=False, pure_json=Fa
     return js
 
 
+def replace_dicts_with_strings(data):
+    return [[str(x) if isinstance(x, dict) else x for x in row] for row in data]
+
+
 def n_suffix_for_bigints(js, pure_json=False):
     def n_suffix(matchobj):
         if pure_json:

src/itables/version.py

@@ -1,3 +1,3 @@
 """ITables' version number"""
 
-__version__ = "2.1.4"
+__version__ = "2.1.5-dev"

tests/test_polars.py

@@ -38,3 +38,16 @@ def test_encode_mixed_contents():
         datatables_rows(df)
         == '[[BigInt("1666767918216000000"), 1699300000000, 0.9510565400123596, -0.30901700258255005]]'
     )
+
+
+def test_value_counts_shown_as_string():
+    """
+    We don't want to pass dicts to datatable
+    as these appear as 'Object', cf. #290
+    """
+    count = polars.DataFrame(["id_1"], schema={"col_1"}).select(
+        polars.col("col_1").value_counts()
+    )
+    assert datatables_rows(count) == [
+        ["{'col_1': 'id_1', 'count': 1}"]
+    ]  # e.g. a str, not a dict