chore: centralize use i18n directive check

Author: AleksandrSl

cmp/compiler/src/plugin/next.ts

@@ -10,6 +10,7 @@ import { createLingoConfig } from "../utils/config-factory";
 import { logger } from "../utils/logger";
 import type { PartialLingoConfig } from "../types";
 import { lingoUnplugin } from "./unplugin";
+import { useI18nRegex } from "./transform/use-i18n";
 
 export type LingoNextPluginOptions = PartialLingoConfig;
 
@@ -87,8 +88,7 @@ function buildLingoConfig(
   // This is more efficient than checking in the loader itself
   if (lingoConfig.useDirective) {
     lingoRuleConfig.condition = {
-      content:
-        /^\s*(?:["']use (?:strict|client|server)["']\s*;?\s*)*["']use i18n["']\s*;?/m,
+      content: useI18nRegex,
     };
   }
 

cmp/compiler/src/plugin/transform/use-i18n.ts

@@ -0,0 +1,2 @@
+export const useI18n = "use i18n";
+export const useI18nRegex = new RegExp(`["']${useI18n}["']`);

cmp/compiler/src/plugin/transform/utils.ts

@@ -3,6 +3,7 @@ import type { NodePath } from "@babel/traverse";
 import type { VariableDeclaration } from "@babel/types";
 import * as t from "@babel/types";
 import { generateTranslationHash } from "../../utils/hash";
+import { useI18n } from "./use-i18n";
 
 type TranslationEntryByType = {
   [T in TranslationEntry as T["type"]]: T;
@@ -104,7 +105,7 @@ export function inferComponentName(path: NodePath<any>): string | null {
 export function hasUseI18nDirective(program: NodePath<t.Program>): boolean {
   const directives = program.node.directives || [];
   return directives.some(
-    (directive: t.Directive) => directive.value.value === "use i18n",
+    (directive: t.Directive) => directive.value.value === useI18n,
   );
 }
 

cmp/compiler/src/plugin/turbopack-loader.ts

@@ -2,7 +2,6 @@ import type { LingoConfig } from "../types";
 import { loadMetadata, saveMetadata, upsertEntries } from "../metadata/manager";
 import { shouldTransformFile, transformComponent } from "./transform";
 import { logger } from "../utils/logger";
-import { hasI18nDirective } from "../utils/directive-check";
 
 /**
  * Turbopack/Webpack loader for automatic translation
@@ -26,17 +25,12 @@ export default async function lingoCompilerTurbopackLoader(
   try {
     const config: LingoConfig = this.getOptions();
 
+    // TODO (AleksandrSl 07/12/2025): Remove too I think
     // Check if this file should be transformed
     if (!shouldTransformFile(this.resourcePath, config)) {
       return callback(null, source);
     }
 
-    // Fast path: if useDirective is enabled, check for directive before parsing
-    // This avoids expensive Babel parsing for files without "use i18n"
-    if (config.useDirective && !hasI18nDirective(source)) {
-      return callback(null, source);
-    }
-
     // Transform the component
     const result = transformComponent({
       code: source,

cmp/compiler/src/plugin/unplugin.ts

@@ -23,6 +23,7 @@ import { saveMetadataWithEntries } from "../metadata/manager";
 import { createLingoConfig } from "../utils/config-factory";
 import { logger } from "../utils/logger";
 import { getCacheDir } from "../utils/path-helpers";
+import { useI18nRegex } from "./transform/use-i18n";
 
 export type LingoPluginOptions = PartialLingoConfig;
 
@@ -84,9 +85,7 @@ export const cacheDir = ${JSON.stringify(cacheDir)};`;
         },
         // If useDirective is enabled, only process files with "use i18n"
         // This is more efficient than checking in the handler
-        code: config.useDirective
-          ? /^\s*(?:["']use (?:strict|client|server)["']\s*;?\s*)*["']use i18n["']\s*;?/m
-          : undefined,
+        code: config.useDirective ? useI18nRegex : undefined,
       },
       handler: async (code, id) => {
         try {