From 54feec5087f8ec03eb70f75e5027b4e65ec8e0c9 Mon Sep 17 00:00:00 2001
From: Egor Smirnov <e.smirnov@corp.vk.com>
Date: Fri, 30 Oct 2026 14:28:06 +0300
Subject: [PATCH] fix: generate named union types referenced by arrays

---
 .gitignore                                 |   1 +
 src/generators/APITypingsGenerator.test.ts | 137 +++++++++++++++++++++
 src/generators/APITypingsGenerator.ts      |   2 +-
 3 files changed, 139 insertions(+), 1 deletion(-)
 create mode 100644 src/generators/APITypingsGenerator.test.ts

diff --git a/.gitignore b/.gitignore
index f06235c..aee5236 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,3 @@
 node_modules
 dist
+.swe-helper/
diff --git a/src/generators/APITypingsGenerator.test.ts b/src/generators/APITypingsGenerator.test.ts
new file mode 100644
index 0000000..0fa464e
--- /dev/null
+++ b/src/generators/APITypingsGenerator.test.ts
@@ -0,0 +1,137 @@
+import path from 'path';
+import { Dictionary } from '../types';
+import { APITypingsGenerator } from './APITypingsGenerator';
+import { SchemaObject } from './SchemaObject';
+
+function generateObjects(value: object, additionalObjects: Dictionary<object> = {}) {
+  const objects: Dictionary<object> = {
+    example_value: value,
+    example_container: {
+      type: 'object',
+      properties: {
+        values: {
+          type: 'array',
+          items: { $ref: '#/definitions/example_value' },
+        },
+      },
+    },
+    ...additionalObjects,
+  };
+  const generator = new APITypingsGenerator({
+    needEmit: false,
+    outDirPath: '',
+    methodsPattern: '*',
+    methodsDefinitions: {
+      methods: [
+        {
+          name: 'example.get',
+          access_token_type: ['user'],
+          parameters: [
+            {
+              name: 'items',
+              type: 'array',
+              items: { $ref: '#/definitions/example_container' },
+            },
+          ],
+          responses: { response: { $ref: '#/definitions/base_ok_response' } },
+        },
+      ],
+    },
+    objects: objects as Dictionary<SchemaObject>,
+    responses: {},
+    errors: {},
+  });
+
+  generator.generate();
+
+  return generator.resultFiles;
+}
+
+beforeEach(() => {
+  jest.spyOn(console, 'log').mockImplementation(() => undefined);
+  jest.spyOn(process, 'exit').mockImplementation((code) => {
+    throw new Error(`process.exit(${code})`);
+  });
+});
+
+afterEach(() => {
+  jest.restoreAllMocks();
+});
+
+test.each([
+  {
+    name: 'a type array with oneOf',
+    schema: {
+      type: ['string', 'integer', 'boolean', 'object', 'array'],
+      oneOf: [
+        { type: 'string' },
+        { type: 'integer' },
+        { type: 'boolean' },
+        { type: 'object', additionalProperties: true },
+        { type: 'array', items: { type: 'object', additionalProperties: true } },
+      ],
+    },
+    expected:
+      'string | number | boolean | { [key: string]: unknown } | { [key: string]: unknown }[]',
+  },
+  {
+    name: 'a type array without oneOf',
+    schema: { type: ['string', 'integer', 'boolean'] },
+    expected: 'string | number | boolean',
+  },
+  {
+    name: 'oneOf without a type',
+    schema: { oneOf: [{ type: 'string' }, { type: 'integer' }] },
+    expected: 'string | number',
+  },
+  {
+    name: 'oneOf with an object type',
+    schema: {
+      type: 'object',
+      oneOf: [{ type: 'object' }, { type: 'array', items: { type: 'integer' } }],
+    },
+    expected: '{ [key: string]: unknown } | number[]',
+  },
+])('generates a named union for $name referenced by array items', ({ schema, expected }) => {
+  const files = generateObjects(schema);
+
+  expect(files[path.join('objects', 'example', 'ExampleValue.ts')]).toContain(
+    `export type ExampleValue = ${expected};`,
+  );
+  expect(files[path.join('objects', 'example', 'ExampleContainer.ts')]).toContain(
+    "import { ExampleValue } from './ExampleValue';",
+  );
+  expect(files[path.join('objects', 'example', 'ExampleContainer.ts')]).toContain(
+    'values?: ExampleValue[];',
+  );
+});
+
+test('generates and imports objects referenced by a named union', () => {
+  const files = generateObjects(
+    {
+      oneOf: [
+        { type: 'string' },
+        { $ref: '#/definitions/example_payload' },
+        { type: 'array', items: { $ref: '#/definitions/example_payload' } },
+      ],
+    },
+    { example_payload: { type: 'object', properties: { id: { type: 'integer' } } } },
+  );
+
+  expect(files[path.join('objects', 'example', 'ExampleValue.ts')]).toContain(
+    "import { ExamplePayload } from './ExamplePayload';",
+  );
+  expect(files[path.join('objects', 'example', 'ExampleValue.ts')]).toContain(
+    'export type ExampleValue = string | ExamplePayload | ExamplePayload[];',
+  );
+  expect(files[path.join('objects', 'example', 'ExamplePayload.ts')]).toContain('id?: number;');
+});
+
+test('preserves interfaces for ordinary objects referenced by array items', () => {
+  const files = generateObjects({ type: 'object', properties: { id: { type: 'integer' } } });
+
+  expect(files[path.join('objects', 'example', 'ExampleValue.ts')]).toContain(
+    'export interface ExampleValue {',
+  );
+  expect(files[path.join('objects', 'example', 'ExampleValue.ts')]).toContain('id?: number;');
+});
diff --git a/src/generators/APITypingsGenerator.ts b/src/generators/APITypingsGenerator.ts
index 565a09b..98027da 100644
--- a/src/generators/APITypingsGenerator.ts
+++ b/src/generators/APITypingsGenerator.ts
@@ -295,7 +295,7 @@ export class APITypingsGenerator {
 
     let result: GeneratorResultInterface | false = false;
 
-    if (object.ref && object.type === 'object') {
+    if (object.oneOf || Array.isArray(object.type) || (object.ref && object.type === 'object')) {
       result = this.getPrimitiveInterfaceCode(object);
     } else {
       switch (object.type) {