next.js config

packages/next-swc/crates/next-core/src/next_client/context.rs

@@ -274,6 +274,8 @@ pub async fn get_client_module_options_context(
         ..module_options_context.clone()
     };
 
+    let use_lightningcss = *next_config.use_lightningcss().await?;
+
     let module_options_context = ModuleOptionsContext {
         // We don't need to resolve React Refresh for each module. Instead,
         // we try resolve it once at the root and pass down a context to all
@@ -302,6 +304,7 @@ pub async fn get_client_module_options_context(
             ),
         ],
         custom_rules,
+        use_lightningcss,
         ..module_options_context
     }
     .cell();

packages/next-swc/crates/next-core/src/next_config.rs

@@ -503,6 +503,8 @@ pub struct ExperimentalConfig {
     /// (doesn't apply to Turbopack).
     webpack_build_worker: Option<bool>,
     worker_threads: Option<bool>,
+
+    use_lightningcss: Option<bool>,
 }
 
 #[derive(Clone, Debug, PartialEq, Serialize, Deserialize, TraceRawVcs)]
@@ -754,6 +756,13 @@ impl NextConfig {
     pub async fn enable_taint(self: Vc<Self>) -> Result<Vc<bool>> {
         Ok(Vc::cell(self.await?.experimental.taint.unwrap_or(false)))
     }
+
+    #[turbo_tasks::function]
+    pub async fn use_lightningcss(self: Vc<Self>) -> Result<Vc<bool>> {
+        Ok(Vc::cell(
+            self.await?.experimental.use_lightningcss.unwrap_or(false),
+        ))
+    }
 }
 
 fn next_configs() -> Vc<Vec<String>> {

packages/next-swc/crates/next-core/src/next_server/context.rs

@@ -360,9 +360,12 @@ pub async fn get_server_module_options_context(
                 },
             );
 
+            let use_lightningcss = *next_config.use_lightningcss().await?;
+
             let module_options_context = ModuleOptionsContext {
                 execution_context: Some(execution_context),
                 esm_url_rewrite_behavior: url_rewrite_behavior,
+                use_lightningcss,
                 ..Default::default()
             };