fix: don't mutate the object being traversed (#54)

* chore: add test for bundling circule $refs

* fix: lint

* fix: handle circular $refs

Author: lottamus

src/__tests__/bundle.spec.ts

@@ -1,6 +1,7 @@
 import { cloneDeep } from 'lodash';
 
 import { BUNDLE_ROOT, bundleTarget } from '../bundle';
+import { safeStringify } from '../safeStringify';
 
 describe('bundleTargetPath()', () => {
   it('should work', () => {
@@ -258,4 +259,76 @@ describe('bundleTargetPath()', () => {
       },
     });
   });
+
+  it('should handle circular $ref', () => {
+    const document = {
+      openapi: '3.0.0',
+      components: {
+        schemas: {
+          Hello: {
+            title: 'Hello',
+            type: 'object',
+            properties: {
+              Hello: {
+                $ref: '#/components/schemas/Hello',
+              },
+              World: {
+                $ref: '#/components/schemas/World',
+              },
+            },
+          },
+          World: {
+            title: 'World',
+            type: 'object',
+            properties: {
+              name: {
+                type: 'string',
+              },
+            },
+          },
+        },
+      },
+    };
+
+    const clone = cloneDeep(document);
+
+    const result = bundleTarget({
+      document: clone,
+      path: '#/components/schemas/Hello',
+    });
+
+    // Do not mutate document
+    expect(clone).toEqual(document);
+
+    expect(safeStringify(result)).toEqual(
+      safeStringify({
+        [BUNDLE_ROOT]: {
+          components: {
+            schemas: {
+              Hello: '[Circular]',
+              World: {
+                properties: {
+                  name: {
+                    type: 'string',
+                  },
+                },
+                title: 'World',
+                type: 'object',
+              },
+            },
+          },
+        },
+        properties: {
+          Hello: {
+            $ref: `#/${BUNDLE_ROOT}/components/schemas/Hello`,
+          },
+          World: {
+            $ref: `#/${BUNDLE_ROOT}/components/schemas/World`,
+          },
+        },
+        title: 'Hello',
+        type: 'object',
+      }),
+    );
+  });
 });

src/bundle.ts

@@ -11,7 +11,13 @@ export const BUNDLE_ROOT = '__bundled__';
 export const bundleTarget = <T = unknown>({ document, path }: { document: T; path: string }, cur?: unknown) =>
   _bundle(cloneDeep(document), path, cur);
 
-const _bundle = (document: unknown, path: string, cur?: unknown, bundledRefInventory: any = {}) => {
+const _bundle = (
+  document: unknown,
+  path: string,
+  cur?: unknown,
+  bundledRefInventory: any = {},
+  bundledObj: any = {},
+) => {
   const objectToBundle = get(document, pointerToPath(path));
 
   traverse(cur ? cur : objectToBundle, ({ parent }) => {
@@ -39,21 +45,23 @@ const _bundle = (document: unknown, path: string, cur?: unknown, bundledRefInven
           pathProcessed.push(key);
 
           const inventoryPathProcessed = [BUNDLE_ROOT, ...pathProcessed];
-          if (has(objectToBundle, inventoryPathProcessed)) continue;
+          if (has(bundledObj, inventoryPathProcessed)) continue;
 
           const target = get(document, pathProcessed);
           if (Array.isArray(target)) {
-            set(objectToBundle, inventoryPathProcessed, []);
+            set(bundledObj, inventoryPathProcessed, []);
           } else if (typeof target === 'object') {
-            set(objectToBundle, inventoryPathProcessed, {});
+            set(bundledObj, inventoryPathProcessed, {});
           }
         }
 
-        set(objectToBundle, inventoryPath, bundled$Ref);
-        _bundle(document, path, bundled$Ref, bundledRefInventory);
+        set(bundledObj, inventoryPath, bundled$Ref);
+        _bundle(document, path, bundled$Ref, bundledRefInventory, bundledObj);
       }
     }
   });
 
+  set(objectToBundle, BUNDLE_ROOT, bundledObj[BUNDLE_ROOT]);
+
   return objectToBundle;
 };