biomejs · ematipico · Nov 22, 2025 · Nov 5, 2025 · Nov 5, 2025 · Nov 6, 2025
diff --git a/.changeset/funny-pans-act.md b/.changeset/funny-pans-act.md
@@ -0,0 +1,7 @@
+---
+"@biomejs/biome": patch
+---
+
+Added support for dollar-sign-prefixed filenames in the [`useFilenamingConvention`](https://biomejs.dev/linter/rules/use-filenaming-convention/) rule.
+
+Biome now allows filenames starting with the dollar-sign (e.g. `$postId.tsx`) by default to support naming conventions used by frameworks such as [TanStack Start](https://tanstack.com/start/latest/docs/framework/react/guide/routing#file-based-routing) for file-based-routing.
diff --git a/crates/biome_js_analyze/src/lint/style/use_filenaming_convention.rs b/crates/biome_js_analyze/src/lint/style/use_filenaming_convention.rs
@@ -24,15 +24,16 @@ declare_lint_rule! {
     ///
     /// The rule supports the following exceptions:
     ///
-    /// - The name of the file can start with a dot or a plus sign, be prefixed and suffixed by underscores `_`.
-    ///   For example, `.filename.js`, `+filename.js`, `__filename__.js`, or even `.__filename__.js`.
+    /// - The name of the file can start with a dot, a plus sign, or a dollar sign, be prefixed and suffixed by underscores `_`.
+    ///   For example, `.filename.js`, `+filename.js`, `$filename.js`, `__filename__.js`, or even `.__filename__.js`.
     ///
-    ///   The convention of prefixing a filename with a plus sign is used by [Sveltekit](https://kit.svelte.dev/docs/routing#page) and [Vike](https://vike.dev/route).
+    ///   - The convention of prefixing a filename with a plus sign is used by [Sveltekit](https://kit.svelte.dev/docs/routing#page) and [Vike](https://vike.dev/route).
+    ///   - The convention of prefixing a filename with a dollar sign is used by [TanStack Start](https://tanstack.com/start/latest/docs/framework/react/guide/routing#file-based-routing) for file-based routing.
     ///
     /// - Also, the rule supports dynamic route syntaxes of [Next.js](https://nextjs.org/docs/pages/building-your-application/routing/dynamic-routes#catch-all-segments), [SolidStart](https://docs.solidjs.com/solid-start/building-your-application/routing#renaming-index), [Nuxt](https://nuxt.com/docs/guide/directory-structure/server#catch-all-route), and [Astro](https://docs.astro.build/en/guides/routing/#rest-parameters).
     ///   For example `[...slug].js` and `[[...slug]].js` are valid filenames.
     ///
-    /// Note that if you specify the `match' option, the previous exceptions will no longer be handled.
+    /// Note that if you specify the `match` option, the previous exceptions will no longer be handled.
     ///
     /// ## Ignoring some files
     ///
@@ -217,7 +218,9 @@ impl Rule for UseFilenamingConvention {
             //
             // Support [Sveltekit](https://kit.svelte.dev/docs/routing#page) and
             // [Vike](https://vike.dev/route) routing conventions where page name starts with `+`.
-            let file_name = if matches!(first_char, b'.' | b'+') {
+            //
+            // Support filenames starting with `$`.
+            let file_name = if matches!(first_char, b'.' | b'+' | b'$') {
                 &file_name[1..]
             } else {
                 file_name
@@ -306,6 +309,8 @@ impl Rule for UseFilenamingConvention {
                     split.next()?
                 } else if let Some(stripped_name) = name.strip_prefix('+') {
                     stripped_name
+                } else if let Some(stripped_name) = name.strip_prefix('$') {
+                    stripped_name
                 } else {
                     name
                 };

diff --git a/crates/biome_js_analyze/tests/specs/style/useFilenamingConvention/$INVALID.js b/crates/biome_js_analyze/tests/specs/style/useFilenamingConvention/$INVALID.js
@@ -0,0 +1,2 @@
+/* should generate diagnostics */
+
diff --git a/crates/biome_js_analyze/tests/specs/style/useFilenamingConvention/$INVALID.js.snap b/crates/biome_js_analyze/tests/specs/style/useFilenamingConvention/$INVALID.js.snap
@@ -0,0 +1,22 @@
+---
+source: crates/biome_js_analyze/tests/spec_tests.rs
+expression: $INVALID.js
+---
+# Input
+```js
+/* should generate diagnostics */
+
+
+```
+
+# Diagnostics
+```
+$INVALID.js lint/style/useFilenamingConvention ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+
+  i The filename should be in camelCase or kebab-case or snake_case or equal to the name of an export.
+  
+  i The filename could be renamed to one of the following names:
+    $invalid.js
+  
+
+```
diff --git a/crates/biome_js_analyze/tests/specs/style/useFilenamingConvention/$dollarValid.js b/crates/biome_js_analyze/tests/specs/style/useFilenamingConvention/$dollarValid.js
@@ -0,0 +1,2 @@
+/* should not generate diagnostics */
+
diff --git a/crates/biome_js_analyze/tests/specs/style/useFilenamingConvention/$dollarValid.js.snap b/crates/biome_js_analyze/tests/specs/style/useFilenamingConvention/$dollarValid.js.snap
@@ -0,0 +1,10 @@
+---
+source: crates/biome_js_analyze/tests/spec_tests.rs
+expression: $dollarValid.js
+---
+# Input
+```js
+/* should not generate diagnostics */
+
+
+```
diff --git a/crates/biome_js_analyze/tests/specs/style/useFilenamingConvention/$dollar_snake.js b/crates/biome_js_analyze/tests/specs/style/useFilenamingConvention/$dollar_snake.js
@@ -0,0 +1,2 @@
+/* should not generate diagnostics */
+
diff --git a/crates/biome_js_analyze/tests/specs/style/useFilenamingConvention/$dollar_snake.js.snap b/crates/biome_js_analyze/tests/specs/style/useFilenamingConvention/$dollar_snake.js.snap
@@ -0,0 +1,10 @@
+---
+source: crates/biome_js_analyze/tests/spec_tests.rs
+expression: $dollar_snake.js
+---
+# Input
+```js
+/* should not generate diagnostics */
+
+
+```