Add support for i18n config in Turbopack (#56182)

Add support for `i18n` in Turbopack.
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Co-authored-by: Will Binns-Smith <wbinnssmith@gmail.com>

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

@@ -139,6 +139,28 @@ pub async fn env_for_js(
         },
     );
 
+    map.insert(
+        "__NEXT_I18N_SUPPORT".to_string(),
+        // How do I check if i18n exists in the config?
+        if next_config.i18n.is_none() {
+            "false".to_string()
+        } else {
+            "true".to_string()
+        },
+    );
+
+    map.insert(
+        "__NEXT_I18N_DOMAINS".to_string(),
+        // Don't stringify undefined
+        match next_config.i18n.as_ref() {
+            Some(i18n) => match i18n.domains.as_ref() {
+                Some(domains) => serde_json::to_string(domains)?,
+                None => "undefined".to_string(),
+            },
+            None => "undefined".to_string(),
+        },
+    );
+
     if !test_mode.is_empty() {
         map.insert("__NEXT_TEST_MODE".to_string(), "true".to_string());
     }

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

@@ -107,7 +107,6 @@ fn defines(
         process.env.__NEXT_CLIENT_ROUTER_D_FILTER = serde_json::to_value(&filter.dynamic_filter)?,
         process.env.__NEXT_DIST_DIR = dist_root_path.to_string(),
         process.env.__NEXT_HAS_REWRITES = true,
-        process.env.__NEXT_I18N_SUPPORT = false,
     ))
 }
 

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

@@ -90,6 +90,7 @@ pub struct NextConfig {
     pub base_path: Option<String>,
     pub skip_middleware_url_normalize: Option<bool>,
     pub skip_trailing_slash_redirect: Option<bool>,
+    pub i18n: Option<I18NConfig>,
 
     ///
     #[serde(rename = "_originalRedirects")]
@@ -115,7 +116,6 @@ pub struct NextConfig {
     generate_build_id: Option<serde_json::Value>,
     generate_etags: bool,
     http_agent_options: HttpAgentConfig,
-    i18n: Option<I18NConfig>,
     on_demand_entries: OnDemandEntriesConfig,
     optimize_fonts: bool,
     output_file_tracing: bool,
@@ -176,20 +176,20 @@ struct HttpAgentConfig {
 
 #[derive(Clone, Debug, PartialEq, Serialize, Deserialize, TraceRawVcs)]
 #[serde(rename_all = "camelCase")]
-struct DomainLocale {
-    default_locale: String,
-    domain: String,
-    http: Option<bool>,
-    locales: Option<Vec<String>>,
+pub struct DomainLocale {
+    pub default_locale: String,
+    pub domain: String,
+    pub http: Option<bool>,
+    pub locales: Option<Vec<String>>,
 }
 
 #[derive(Clone, Debug, PartialEq, Serialize, Deserialize, TraceRawVcs)]
 #[serde(rename_all = "camelCase")]
-struct I18NConfig {
-    default_locale: String,
-    domains: Option<Vec<DomainLocale>>,
-    locale_detection: Option<bool>,
-    locales: Vec<String>,
+pub struct I18NConfig {
+    pub default_locale: String,
+    pub domains: Option<Vec<DomainLocale>>,
+    pub locale_detection: Option<bool>,
+    pub locales: Vec<String>,
 }
 
 #[derive(Clone, Debug, PartialEq, Serialize, Deserialize, TraceRawVcs)]

packages/next/src/lib/turbopack-warning.ts

@@ -21,8 +21,10 @@ const supportedTurbopackNextConfigOptions = [
   'swcMinify',
   'transpilePackages',
   'trailingSlash',
-  'i18n.locales',
   'i18n.defaultLocale',
+  'i18n.domains',
+  'i18n.localeDetection',
+  'i18n.locales',
   'sassOptions',
   'configOrigin',
   'httpAgentOptions',