fixes

react-openapi/src/components/fields/renderers/DiscriminatorField.tsx

@@ -15,13 +15,21 @@ export function DiscriminatorField({ field, value, onChange, error }: Props) {
   const discProp = field.discriminatorProperty ?? "type";
   const currentType = value?.[discProp] ?? "";
 
+  function defaultFieldValue(field: FieldConfig): any {
+    if (field.enumValues) return field.enumValues[0];
+    if (field.isArray) return [];
+    if (field.type === "object") return {};
+    if (field.type === "number" || field.type === "integer") return 0;
+    return null;
+  }
+
   const handleTypeChange = useCallback((e: any) => {
     const newType = e.target.value;
     const option = options.find((o) => o.value === newType);
     const newValue: Record<string, any> = { [discProp]: newType };
     if (option) {
       for (const f of option.fields) {
-        newValue[f.name] = f.enumValues?.[0] ?? f.type === "number" ? 0 : f.type === "integer" ? 0 : "";
+        newValue[f.name] = defaultFieldValue(f);
       }
     }
     onChange(newValue);

react-openapi/src/components/fields/renderers/JsonField.tsx

@@ -243,6 +243,10 @@ function buildDefaultShape(fields: FieldConfig[], schemas: Record<string, any>):
       const refSchemaObj = schemas[f.refSchema!];
       const nestedFields = refSchemaObj ? extractFields(f.refSchema!, refSchemaObj, schemas) : [];
       shape[f.name] = f.isArray ? [] : buildDefaultShape(nestedFields, schemas);
+    } else if (f.isArray) {
+      shape[f.name] = [];
+    } else if (f.type === "object") {
+      shape[f.name] = {};
     } else {
       shape[f.name] = null;
     }
@@ -254,7 +258,7 @@ function initEditValue(value: any, field: FieldConfig, schemas: Record<string, a
   if (field.isArray) {
     return value ? value.map((item: any) => ({ ...item })) : [];
   }
-  if (value && typeof value === "object") {
+  if (value != null && value !== "" && typeof value === "object") {
     return { ...value };
   }
   return buildDefaultShape(