From 18efaf397a6bab8bd5dba881bbdfeceef8dbafb0 Mon Sep 17 00:00:00 2001
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 <netroy@users.noreply.github.com>
Date: Mon, 27 Mar 2023 16:22:59 +0200
Subject: [PATCH] fix(core): Do not mark duplicates as circular references in
 `jsonStringify` (#5789)

* fix(core): jsonStringify should not mark duplicates as circular references

* not mark duplicates as circular references in the code node as well
---
 packages/nodes-base/nodes/Code/utils.ts |  6 ++----
 packages/workflow/src/utils.ts          | 27 +++++++++++--------------
 packages/workflow/test/utils.test.ts    |  8 ++++++++
 3 files changed, 22 insertions(+), 19 deletions(-)

diff --git a/packages/nodes-base/nodes/Code/utils.ts b/packages/nodes-base/nodes/Code/utils.ts
index d4adfde155..67726f1485 100644
--- a/packages/nodes-base/nodes/Code/utils.ts
+++ b/packages/nodes-base/nodes/Code/utils.ts
@@ -12,9 +12,7 @@ function isTraversable(maybe: unknown): maybe is IDataObject {
  * Stringify any non-standard JS objects (e.g. `Date`, `RegExp`) inside output items at any depth.
  */
 export function standardizeOutput(output: IDataObject) {
-	const knownObjects = new WeakSet();
-
-	function standardizeOutputRecursive(obj: IDataObject): IDataObject {
+	function standardizeOutputRecursive(obj: IDataObject, knownObjects = new WeakSet()): IDataObject {
 		for (const [key, value] of Object.entries(obj)) {
 			if (!isTraversable(value)) continue;
 
@@ -29,7 +27,7 @@ export function standardizeOutput(output: IDataObject) {
 			obj[key] =
 				value.constructor.name !== 'Object'
 					? JSON.stringify(value) // Date, RegExp, etc.
-					: standardizeOutputRecursive(value);
+					: standardizeOutputRecursive(value, knownObjects);
 		}
 		return obj;
 	}
diff --git a/packages/workflow/src/utils.ts b/packages/workflow/src/utils.ts
index 6f7a9fdad1..b1ada63be1 100644
--- a/packages/workflow/src/utils.ts
+++ b/packages/workflow/src/utils.ts
@@ -64,27 +64,24 @@ export const jsonParse = <T>(jsonString: string, options?: JSONParseOptions<T>):
 
 type JSONStringifyOptions = {
 	replaceCircularRefs?: boolean;
-	circularRefReplacement?: string;
 };
 
-const getReplaceCircularReferencesFn = (options: JSONStringifyOptions) => {
-	const knownObjects = new WeakSet();
-	return (key: any, value: any) => {
-		if (typeof value === 'object' && value !== null) {
-			if (knownObjects.has(value)) {
-				return options?.circularRefReplacement ?? '[Circular Reference]';
-			}
-			knownObjects.add(value);
+const replaceCircularReferences = <T>(value: T, knownObjects = new WeakSet()): T => {
+	if (value && typeof value === 'object') {
+		if (knownObjects.has(value)) return '[Circular Reference]' as T;
+		knownObjects.add(value);
+		const copy = (Array.isArray(value) ? [] : {}) as T;
+		for (const key in value) {
+			copy[key] = replaceCircularReferences(value[key], knownObjects);
 		}
-		return value;
-	};
+		knownObjects.delete(value);
+		return copy;
+	}
+	return value;
 };
 
 export const jsonStringify = (obj: unknown, options: JSONStringifyOptions = {}): string => {
-	const replacer = options?.replaceCircularRefs
-		? getReplaceCircularReferencesFn(options)
-		: undefined;
-	return JSON.stringify(obj, replacer);
+	return JSON.stringify(options?.replaceCircularRefs ? replaceCircularReferences(obj) : obj);
 };
 
 export const sleep = async (ms: number): Promise<void> =>
diff --git a/packages/workflow/test/utils.test.ts b/packages/workflow/test/utils.test.ts
index 0cc34f4ef4..fb944ec62a 100644
--- a/packages/workflow/test/utils.test.ts
+++ b/packages/workflow/test/utils.test.ts
@@ -30,6 +30,14 @@ describe('jsonStringify', () => {
 			'{"a":1,"b":2,"c":"[Circular Reference]"}',
 		);
 	});
+
+	it('should not detect duplicates as circular references', () => {
+		const y = { z: 5 };
+		const x = [y, y, { y }];
+		expect(jsonStringify(x, { replaceCircularRefs: true })).toEqual(
+			'[{"z":5},{"z":5},{"y":{"z":5}}]',
+		);
+	});
 });
 
 describe('deepCopy', () => {