fixes createDefaultValue doesn't follow anyOf, oneOf, allOf #2401

packages/core/src/mappers/renderer.ts

@@ -168,9 +168,13 @@ export const showAsRequired = (
  */
 export const createDefaultValue = (
   schema: JsonSchema,
-  rootSchema: JsonSchema
-) => {
-  const resolvedSchema = Resolve.schema(schema, schema.$ref, rootSchema);
+  rootSchema: JsonSchema,
+  defaultValue: any = {}
+): any => {
+  const resolvedSchema =
+    typeof schema.$ref === 'string'
+      ? Resolve.schema(rootSchema, schema.$ref, rootSchema)
+      : schema;
   if (resolvedSchema.default !== undefined) {
     return extractDefaults(resolvedSchema, rootSchema);
   }
@@ -196,9 +200,62 @@ export const createDefaultValue = (
     return extractDefaults(resolvedSchema, rootSchema);
   } else if (hasType(resolvedSchema, 'null')) {
     return null;
-  } else {
-    return {};
   }
+
+  let combinatorDefault = undefined;
+
+  combinatorDefault = createDefaultValueForCombinatorSchema(
+    schema.oneOf,
+    rootSchema
+  );
+  if (combinatorDefault !== undefined) {
+    return combinatorDefault;
+  }
+
+  combinatorDefault = createDefaultValueForCombinatorSchema(
+    schema.anyOf,
+    rootSchema
+  );
+  if (combinatorDefault !== undefined) {
+    return combinatorDefault;
+  }
+
+  combinatorDefault = createDefaultValueForCombinatorSchema(
+    schema.allOf,
+    rootSchema
+  );
+  if (combinatorDefault !== undefined) {
+    return combinatorDefault;
+  }
+
+  return defaultValue;
+};
+
+const createDefaultValueForCombinatorSchema = (
+  combinatorSchema: JsonSchema[],
+  rootSchema: JsonSchema
+) => {
+  if (
+    combinatorSchema &&
+    Array.isArray(combinatorSchema) &&
+    combinatorSchema.length > 0
+  ) {
+    const noDefaultValue = Symbol.for('noDefaultValue');
+    for (const combineSchema of combinatorSchema) {
+      const result = createDefaultValue(
+        combineSchema,
+        rootSchema,
+        noDefaultValue
+      );
+      if (result !== noDefaultValue) {
+        // return the first one that have type information
+        return result;
+      }
+    }
+  }
+
+  // no default value found
+  return undefined;
 };
 
 /**