From 339a4abf8424070b9a05acf85307185405e0cbe3 Mon Sep 17 00:00:00 2001
From: shadow-light <42055707+shadow-light@users.noreply.github.com>
Date: Tue, 6 Jun 2023 10:22:09 +1000
Subject: [PATCH 1/3] pattern can be RegExp

---
 packages/netlify-cms-core/index.d.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/netlify-cms-core/index.d.ts b/packages/netlify-cms-core/index.d.ts
index 54ca3ec3dd99..c58330aa6349 100644
--- a/packages/netlify-cms-core/index.d.ts
+++ b/packages/netlify-cms-core/index.d.ts
@@ -63,7 +63,7 @@ declare module 'netlify-cms-core' {
     label?: string;
     required?: boolean;
     hint?: string;
-    pattern?: [string, string];
+    pattern?: [string | RegExp, string];
     i18n?: boolean | 'translate' | 'duplicate' | 'none';
     media_folder?: string;
     public_folder?: string;

From 32f9dd2bf48b83fa6ddba111d9a7380ebf6cc2d9 Mon Sep 17 00:00:00 2001
From: Yan <61414485+yanthomasdev@users.noreply.github.com>
Date: Tue, 19 May 2026 15:52:08 -0300
Subject: [PATCH 2/3] fix: other pattern types

---
 packages/decap-cms-core/index.d.ts         | 2 +-
 packages/decap-cms-core/src/types/redux.ts | 6 +++---
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/packages/decap-cms-core/index.d.ts b/packages/decap-cms-core/index.d.ts
index fcae20c10334..9469c5802de4 100644
--- a/packages/decap-cms-core/index.d.ts
+++ b/packages/decap-cms-core/index.d.ts
@@ -299,7 +299,7 @@ declare module 'decap-cms-core' {
   export interface ViewFilter {
     label: string;
     field: string;
-    pattern: string;
+    pattern: string | boolean;
   }
 
   export interface ViewGroup {
diff --git a/packages/decap-cms-core/src/types/redux.ts b/packages/decap-cms-core/src/types/redux.ts
index ef31fbfc0a1e..3f3f3d7c702d 100644
--- a/packages/decap-cms-core/src/types/redux.ts
+++ b/packages/decap-cms-core/src/types/redux.ts
@@ -72,7 +72,7 @@ export interface CmsFieldBase {
   label?: string;
   required?: boolean;
   hint?: string;
-  pattern?: [string, string];
+  pattern?: [string | RegExp, string];
   i18n?: boolean | 'translate' | 'duplicate' | 'none';
   media_folder?: string;
   public_folder?: string;
@@ -315,14 +315,14 @@ export interface CmsCollectionFile {
 export interface ViewFilter {
   label: string;
   field: string;
-  pattern: string;
+  pattern: string | boolean;
   id: string;
 }
 
 export interface ViewGroup {
   label: string;
   field: string;
-  pattern: string;
+  pattern?: string;
   id: string;
 }
 

From 1792538d768c16ef8e957a16019102c247336d87 Mon Sep 17 00:00:00 2001
From: Yan <61414485+yanthomasdev@users.noreply.github.com>
Date: Tue, 19 May 2026 15:53:40 -0300
Subject: [PATCH 3/3] fix: add guard for undefined pattern

---
 packages/decap-cms-core/src/reducers/entries.ts | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/packages/decap-cms-core/src/reducers/entries.ts b/packages/decap-cms-core/src/reducers/entries.ts
index 653b77aee867..e651bcf6768b 100644
--- a/packages/decap-cms-core/src/reducers/entries.ts
+++ b/packages/decap-cms-core/src/reducers/entries.ts
@@ -474,14 +474,16 @@ function getGroup(entry: EntryMap, selectedGroup: GroupMap) {
   if (selectedGroup.has('pattern')) {
     const pattern = selectedGroup.get('pattern');
     let value = '';
-    try {
-      const regex = new RegExp(pattern);
-      const matched = dataAsString.match(regex);
-      if (matched) {
-        value = matched[0];
+    if (pattern !== undefined) {
+      try {
+        const regex = new RegExp(pattern);
+        const matched = dataAsString.match(regex);
+        if (matched) {
+          value = matched[0];
+        }
+      } catch (e) {
+        console.warn(`Invalid view group pattern '${pattern}' for field '${field}'`, e);
       }
-    } catch (e) {
-      console.warn(`Invalid view group pattern '${pattern}' for field '${field}'`, e);
     }
     return {
       id: `${label}${value}`,