WIP: working webpack by separating next and generic webpack

Author: AleksandrSl

cmp/compiler/package.json

@@ -86,25 +86,25 @@
       "import": "./build/plugin/webpack.mjs",
       "require": "./build/plugin/webpack.cjs"
     },
-    "./turbopack-loader": {
-      "types": "./build/plugin/turbopack-loader.d.ts",
-      "import": "./build/plugin/turbopack-loader.mjs",
-      "require": "./build/plugin/turbopack-loader.cjs"
+    "./next-compiler-loader": {
+      "types": "./build/plugin/next-compiler-loader.d.ts",
+      "import": "./build/plugin/next-compiler-loader.mjs",
+      "require": "./build/plugin/next-compiler-loader.cjs"
     },
-    "./dev-server-loader": {
-      "types": "./build/plugin/dev-server-loader.d.ts",
-      "import": "./build/plugin/dev-server-loader.mjs",
-      "require": "./build/plugin/dev-server-loader.cjs"
+    "./next-dev-config-loader": {
+      "types": "./build/plugin/next-dev-config-loader.d.ts",
+      "import": "./build/plugin/next-dev-config-loader.mjs",
+      "require": "./build/plugin/next-dev-config-loader.cjs"
     },
-    "./turbopack-locale-server-loader": {
-      "types": "./build/plugin/turbopack-locale-server-loader.d.ts",
-      "import": "./build/plugin/turbopack-locale-server-loader.mjs",
-      "require": "./build/plugin/turbopack-locale-server-loader.cjs"
+    "./next-locale-server-loader": {
+      "types": "./build/plugin/next-locale-server-loader.d.ts",
+      "import": "./build/plugin/next-locale-server-loader.mjs",
+      "require": "./build/plugin/next-locale-server-loader.cjs"
     },
-    "./turbopack-locale-client-loader": {
-      "types": "./build/plugin/turbopack-locale-client-loader.d.ts",
-      "import": "./build/plugin/turbopack-locale-client-loader.mjs",
-      "require": "./build/plugin/turbopack-locale-client-loader.cjs"
+    "./next-locale-client-loader": {
+      "types": "./build/plugin/next-locale-client-loader.d.ts",
+      "import": "./build/plugin/next-locale-client-loader.mjs",
+      "require": "./build/plugin/next-locale-client-loader.cjs"
     }
   },
   "files": [

cmp/compiler/src/plugin/dev-server-loader.ts

@@ -1,16 +1,34 @@
 /**
  * Shared code generation for locale resolution modules
  * Used by both unplugin (virtual modules) and Turbopack loaders
+ *
+ * This module provides FULL module generators, not just function bodies.
+ * Both loaders and unplugin use these to generate complete modules.
  */
 
 import type { LingoConfig } from "../types";
+import { getCacheDir } from "../utils/path-helpers";
 
 /**
- * Generate server-side locale detection code
- * Reads locale from cookie
+ * Generate complete dev-config module
+ * Exports serverUrl and cacheDir constants
  */
-export function generateServerLocaleCode(config: LingoConfig): string {
+export function generateDevConfigModule(config: LingoConfig): string {
+  const serverUrl = config.dev.translationServerUrl || "http://127.0.0.1:60000";
+  const cacheDir = getCacheDir(config);
+
+  return `export const serverUrl = ${JSON.stringify(serverUrl)};
+export const cacheDir = ${JSON.stringify(cacheDir)};
+`;
+}
+
+/**
+ * Generate complete locale/server module
+ * Exports async getServerLocale() function
+ */
+export function generateServerLocaleModule(config: LingoConfig): string {
   return `
+export async function getServerLocale() {
   try {
     const { cookies } = await import('next/headers');
     const cookieStore = await cookies();
@@ -19,31 +37,33 @@ export function generateServerLocaleCode(config: LingoConfig): string {
   } catch (error) {
     // Fallback if cookies are not available
     return ${JSON.stringify(config.sourceLocale)};
-  }`;
+  }
+}
+`;
 }
 
 /**
- * Generate client-side locale detection and persistence code
- * Includes both getClientLocale() and persistLocale() functions
+ * Generate complete locale/client module
+ * Exports getClientLocale() and persistLocale() functions
  */
-export function generateClientLocaleCode(config: LingoConfig): {
-  getClientLocale: string;
-  persistLocale: string;
-} {
+export function generateClientLocaleModule(config: LingoConfig): string {
   const cookieName = config.cookieConfig.name;
   const maxAge = config.cookieConfig.maxAge;
 
-  return {
-    getClientLocale: `
+  return `
+export function getClientLocale() {
   if (typeof document !== 'undefined') {
     const match = document.cookie.match(/${cookieName}=([^;]+)/);
     if (match) return match[1];
   }
   // Fallback to source locale
   return ${JSON.stringify(config.sourceLocale)};
-`,
-    persistLocale: `if (typeof document !== 'undefined') {
+}
+
+export function persistLocale(locale) {
+  if (typeof document !== 'undefined') {
     document.cookie = \`${cookieName}=\${locale}; path=/; max-age=${maxAge}\`;
-  }`,
-  };
+  }
+}
+`;
 }

cmp/compiler/src/plugin/locale-code-generator.ts

@@ -11,10 +11,11 @@ import { MetadataManager } from "../metadata/manager";
  * For production builds, translations are generated after compilation completes
  * via Next.js's runAfterProductionCompile hook (see next.ts plugin).
  */
-export default async function lingoCompilerTurbopackLoader(
+export default async function nextCompilerLoader(
   this: any,
   source: string,
 ): Promise<void> {
+  // TODO (AleksandrSl 14/12/2025): Webpack doesn't like callback usage in async function. But asycn function can return only code, so we have to use promises which is sad.
   // Ensure we're running in loader context
   if (typeof this.async !== "function") {
     throw new Error("This module must be run as a loader");
@@ -55,10 +56,27 @@ export default async function lingoCompilerTurbopackLoader(
       );
     }
 
-    callback(null, result.code, result.map);
+    // Validate source map before passing to webpack
+    // Webpack crashes if sources array contains undefined values
+    const validMap =
+      result.map &&
+      result.map.sources &&
+      Array.isArray(result.map.sources) &&
+      result.map.sources.every((s: any) => typeof s === "string")
+        ? result.map
+        : undefined;
+
+    callback(null, result.code, validMap);
   } catch (error) {
     logger.error(`Compiler failed for ${this.resourcePath}:`);
-    logger.error("Details:", error);
+    logger.error(
+      "Details:",
+      error,
+      typeof error === "object" && error && "message" in error
+        ? error.message
+        : error,
+      error instanceof Error ? error.stack : undefined,
+    );
     callback(error as Error);
   }
 }

…/compiler/src/plugin/turbopack-loader.ts …piler/src/plugin/next-compiler-loader.tscmp/compiler/src/plugin/turbopack-loader.ts renamed to cmp/compiler/src/plugin/next-compiler-loader.ts cmp/compiler/src/plugin/turbopack-loader.ts renamed to cmp/compiler/src/plugin/next-compiler-loader.ts

@@ -0,0 +1,14 @@
+import type { LingoConfig } from "../types";
+import { generateDevConfigModule } from "./locale-code-generator";
+
+/**
+ * Loader for dev-config module
+ * Generates full module code - ignores source file (template is only for types)
+ */
+export default function nextDevConfigLoader(
+  this: any,
+  _source: string,
+): string {
+  const config: LingoConfig = this.getOptions();
+  return generateDevConfigModule(config);
+}

cmp/compiler/src/plugin/next-dev-config-loader.ts

@@ -0,0 +1,15 @@
+/**
+ * Loader for locale/client module
+ * Generates full module code - ignores source file (template is only for types)
+ */
+
+import type { LingoConfig } from "../types";
+import { generateClientLocaleModule } from "./locale-code-generator";
+
+export default function nextLocaleClientLoader(
+  this: any,
+  _source: string,
+): string {
+  const config: LingoConfig = this.getOptions();
+  return generateClientLocaleModule(config);
+}

cmp/compiler/src/plugin/next-locale-client-loader.ts

@@ -0,0 +1,15 @@
+/**
+ * Loader for locale/server module
+ * Generates full module code - ignores source file (template is only for types)
+ */
+
+import type { LingoConfig } from "../types";
+import { generateServerLocaleModule } from "./locale-code-generator";
+
+export default function nextLocaleServerLoader(
+  this: any,
+  _source: string,
+): string {
+  const config: LingoConfig = this.getOptions();
+  return generateServerLocaleModule(config);
+}