From 8e1bafbc9921290e5601ab1b8b9ba0505aeb392d Mon Sep 17 00:00:00 2001
From: Valentin Palkovic <valentin@chromatic.com>
Date: Wed, 25 Feb 2026 10:36:16 +0100
Subject: [PATCH] Core: Avoid performance bottlenecks when infering args for
 recursive calls on DOM elemens

---
 .../modules/store/inferArgTypes.ts            | 34 +++++++++++++++----
 1 file changed, 28 insertions(+), 6 deletions(-)

diff --git a/code/core/src/preview-api/modules/store/inferArgTypes.ts b/code/core/src/preview-api/modules/store/inferArgTypes.ts
index 04637f18ac59..f4e69dd6b3c8 100644
--- a/code/core/src/preview-api/modules/store/inferArgTypes.ts
+++ b/code/core/src/preview-api/modules/store/inferArgTypes.ts
@@ -6,7 +6,12 @@ import { dedent } from 'ts-dedent';
 
 import { combineParameters } from './parameters';
 
-const inferType = (value: any, name: string, visited: Set<any>): SBType => {
+const inferType = (
+  value: any,
+  name: string,
+  visited: Set<any>,
+  cache: Map<any, SBType>
+): SBType => {
   const type = typeof value;
   switch (type) {
     case 'boolean':
@@ -19,6 +24,12 @@ const inferType = (value: any, name: string, visited: Set<any>): SBType => {
       break;
   }
   if (value) {
+    // Check cache first for previously computed results
+    if (cache.has(value)) {
+      return cache.get(value)!;
+    }
+
+    // Check for cycles (currently being processed in this path)
     if (visited.has(value)) {
       logger.warn(dedent`
         We've detected a cycle in arg '${name}'. Args should be JSON-serializable.
@@ -29,25 +40,36 @@ const inferType = (value: any, name: string, visited: Set<any>): SBType => {
       `);
       return { name: 'other', value: 'cyclic object' };
     }
+
     visited.add(value);
+
+    let result: SBType;
+
     if (Array.isArray(value)) {
       const childType: SBType =
         value.length > 0
-          ? inferType(value[0], name, new Set(visited))
+          ? inferType(value[0], name, visited, cache)
           : { name: 'other', value: 'unknown' };
-      return { name: 'array', value: childType };
+      result = { name: 'array', value: childType };
+    } else {
+      const fieldTypes = mapValues(value, (field) => inferType(field, name, visited, cache));
+      result = { name: 'object', value: fieldTypes };
     }
-    const fieldTypes = mapValues(value, (field) => inferType(field, name, new Set(visited)));
-    return { name: 'object', value: fieldTypes };
+
+    visited.delete(value); // Remove from current path after processing
+    cache.set(value, result); // Cache the result for future lookups
+
+    return result;
   }
   return { name: 'object', value: {} };
 };
 
 export const inferArgTypes: ArgTypesEnhancer<Renderer> = (context) => {
   const { id, argTypes: userArgTypes = {}, initialArgs = {} } = context;
+  const cache = new Map<any, SBType>();
   const argTypes = mapValues(initialArgs, (arg, key) => ({
     name: key,
-    type: inferType(arg, `${id}.${key}`, new Set()),
+    type: inferType(arg, `${id}.${key}`, new Set(), cache),
   }));
   const userArgTypesNames = mapValues(userArgTypes, (argType, key) => ({
     name: key,