From bc8656d659ff0e1a29796d8c6ef779354d6ff997 Mon Sep 17 00:00:00 2001
From: WK Wong <wingkwong.code@gmail.com>
Date: Tue, 27 Jan 2026 17:34:40 +0800
Subject: [PATCH 1/3] chore(deps): remove flat library

---
 packages/core/theme/package.json | 1 -
 pnpm-lock.yaml                   | 3 ---
 2 files changed, 4 deletions(-)

diff --git a/packages/core/theme/package.json b/packages/core/theme/package.json
index 897732e55a..5276477e06 100644
--- a/packages/core/theme/package.json
+++ b/packages/core/theme/package.json
@@ -49,7 +49,6 @@
     "color": "^4.2.3",
     "color2k": "^2.0.3",
     "deepmerge": "4.3.1",
-    "flat": "^5.0.2",
     "tailwind-variants": "3.2.2",
     "tailwind-merge": "3.4.0",
     "@heroui/shared-utils": "workspace:*"
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index ffdbaf7b8c..03cd61b9ca 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -3228,9 +3228,6 @@ importers:
       deepmerge:
         specifier: 4.3.1
         version: 4.3.1
-      flat:
-        specifier: ^5.0.2
-        version: 5.0.2
       tailwind-merge:
         specifier: 3.4.0
         version: 3.4.0

From 5b80cf67272eaa3daf1c2734aa964041b60f2b1b Mon Sep 17 00:00:00 2001
From: WK Wong <wingkwong.code@gmail.com>
Date: Tue, 27 Jan 2026 17:35:06 +0800
Subject: [PATCH 2/3] refactor(theme): replace flatten from flat

---
 packages/core/theme/src/utils/object.ts | 53 ++++++++++++++++++++++++-
 1 file changed, 51 insertions(+), 2 deletions(-)

diff --git a/packages/core/theme/src/utils/object.ts b/packages/core/theme/src/utils/object.ts
index c320764cd0..60f8911bd3 100644
--- a/packages/core/theme/src/utils/object.ts
+++ b/packages/core/theme/src/utils/object.ts
@@ -1,5 +1,3 @@
-import flatten from "flat";
-
 export function swapColorValues<T extends Object>(colors: T) {
   const swappedColors = {};
   const keys = Object.keys(colors);
@@ -40,6 +38,57 @@ export function removeDefaultKeys<T extends Object>(obj: T) {
   return newObj;
 }
 
+function isBuffer(obj) {
+  return (
+    obj &&
+    obj.constructor &&
+    typeof obj.constructor.isBuffer === "function" &&
+    obj.constructor.isBuffer(obj)
+  );
+}
+
+function keyIdentity(key) {
+  return key;
+}
+
+export function flatten(target, opts) {
+  opts = opts || {};
+
+  const delimiter = opts.delimiter || ".";
+  const maxDepth = opts.maxDepth;
+  const transformKey = opts.transformKey || keyIdentity;
+  const output = {};
+
+  function step(object, prev, currentDepth) {
+    currentDepth = currentDepth || 1;
+    Object.keys(object).forEach(function (key) {
+      const value = object[key];
+      const isarray = opts.safe && Array.isArray(value);
+      const type = Object.prototype.toString.call(value);
+      const isbuffer = isBuffer(value);
+      const isobject = type === "[object Object]" || type === "[object Array]";
+
+      const newKey = prev ? prev + delimiter + transformKey(key) : transformKey(key);
+
+      if (
+        !isarray &&
+        !isbuffer &&
+        isobject &&
+        Object.keys(value).length &&
+        (!opts.maxDepth || currentDepth < maxDepth)
+      ) {
+        return step(value, newKey, currentDepth + 1);
+      }
+
+      output[newKey] = value;
+    });
+  }
+
+  step(target, null, null);
+
+  return output;
+}
+
 /**
  *
  * Flatten theme object and remove default keys

From fa3a58aa992d79c91e13fd6bd5d5c5514c46ef47 Mon Sep 17 00:00:00 2001
From: WK Wong <wingkwong.code@gmail.com>
Date: Tue, 27 Jan 2026 17:35:37 +0800
Subject: [PATCH 3/3] chore: add changeset

---
 .changeset/strong-shoes-exist.md | 5 +++++
 1 file changed, 5 insertions(+)
 create mode 100644 .changeset/strong-shoes-exist.md

diff --git a/.changeset/strong-shoes-exist.md b/.changeset/strong-shoes-exist.md
new file mode 100644
index 0000000000..10eccf1ccd
--- /dev/null
+++ b/.changeset/strong-shoes-exist.md
@@ -0,0 +1,5 @@
+---
+"@heroui/theme": patch
+---
+
+remove flat dependencies (#6148)