Refactoring and bug fixes

backend/utils.py

@@ -0,0 +1,37 @@
+"""
+Utility functions for data conversion and JSON serialization.
+"""
+
+import pandas as pd
+import numpy as np
+from typing import Any, List
+
+
+def convert_to_native(value: Any) -> Any:
+    """Convert numpy types to native Python types for JSON serialization."""
+    if pd.isna(value):
+        return None
+    if isinstance(value, (np.integer,)):
+        return int(value)
+    if isinstance(value, (np.floating,)):
+        if np.isnan(value) or np.isinf(value):
+            return None
+        return float(value)
+    if isinstance(value, np.ndarray):
+        return value.tolist()
+    if value == "SUPP" or value == "NE" or value == "NA" or value == "NP":
+        return None
+    return value
+
+
+def clean_for_json(df: pd.DataFrame) -> List[dict]:
+    """Convert DataFrame to list of dicts, replacing NaN/inf with None for JSON serialization."""
+    records = df.to_dict(orient="records")
+    cleaned = []
+    for record in records:
+        clean_record = {}
+        for key, value in record.items():
+            clean_record[key] = convert_to_native(value)
+        cleaned.append(clean_record)
+    return cleaned
+