Only translate missing keys

examples/i18next/locales/en.json

@@ -5,5 +5,6 @@
   },
   "interpolated": "Have a nice day, {{name}}!",
   "pluralKey_one": "This is a nice example.",
-  "pluralKey_other": "This are nice examples."
+  "pluralKey_other": "This are nice examples.",
+  "missing_translation": "This should work"
 }

examples/i18next/locales/sv.json

@@ -5,5 +5,6 @@
   },
   "interpolated": "Ha en trevlig dag, {{name}}!",
   "pluralKey_one": "Det här är ett fint exempel.",
-  "pluralKey_other": "Det här är fina exempel."
-}
+  "pluralKey_other": "Det här är fina exempel.",
+  "missing_translation": "Detta bör fungera"
+}

examples/next-international/locales/en.ts

@@ -11,5 +11,4 @@ export default {
   "missing.translation.in.fr": "This should work",
   "cows#one": "A cow",
   "cows#other": "{count} cows",
-  "hello.world": "Hello World",
 } as const;

examples/next-international/locales/fr.ts

@@ -1,7 +1,7 @@
 export default {
-  hello: "Bonjour",
-  welcome: "Bonjour {name}!",
-  "about.you": "Bonjour {name}! Vous avez {age} ans",
+  "hello": "Bonjour",
+  "welcome": "Bonjour {name} !",
+  "about.you": "Bonjour {name} ! Vous avez {age} ans",
   "scope.test": "Un domaine",
   "scope.more.test": "Un domaine",
   "scope.more.param": "Un domaine avec {param}",
@@ -11,4 +11,5 @@ export default {
   "missing.translation.in.fr": "Cela devrait fonctionner",
   "cows#one": "Une vache",
   "cows#other": "{count} vaches",
+  "hello.world2": "Bonjour le monde !"
 } as const;

packages/cli/src/commands/diff.ts

@@ -1,7 +1,7 @@
 import { execSync } from "node:child_process";
 import { intro, outro } from "@clack/prompts";
 import chalk from "chalk";
-import { getConfig } from "../utils.js";
+import { extractChangedKeys, getConfig } from "../utils.js";
 
 export async function diff() {
   intro("Checking for changes in source locale file...");
@@ -25,51 +25,25 @@ export async function diff() {
       process.exit(0);
     }
 
-    // Extract changed/added/removed keys from diff
-    const addedKeys = new Set<string>();
-    const removedKeys = new Set<string>();
+    const { addedKeys, removedKeys } = extractChangedKeys(diff);
 
-    for (const line of diff.split("\n")) {
-      if (line.startsWith("+") && !line.startsWith("+++")) {
-        const match = line.match(/['"]([\w_.]+)['"]/);
-        if (match) addedKeys.add(match[1]);
-      } else if (line.startsWith("-") && !line.startsWith("---")) {
-        const match = line.match(/['"]([\w_.]+)['"]/);
-        if (match) removedKeys.add(match[1]);
-      }
-    }
-
-    // Remove keys that appear in both added and removed (these are modifications)
-    for (const key of addedKeys) {
-      if (removedKeys.has(key)) {
-        addedKeys.delete(key);
-        removedKeys.delete(key);
-      }
-    }
-
-    if (addedKeys.size === 0 && removedKeys.size === 0) {
+    if (addedKeys.length === 0 && removedKeys.length === 0) {
       outro(
         chalk.yellow("No translation keys were added, modified or removed."),
       );
       process.exit(0);
     }
 
-    let message = "";
-    if (addedKeys.size > 0) {
-      message += chalk.green(
-        `Found ${addedKeys.size} added translation key${addedKeys.size === 1 ? "" : "s"}\n`,
-      );
-    }
-    if (removedKeys.size > 0) {
-      message += chalk.red(
-        `Found ${removedKeys.size} removed translation key${removedKeys.size === 1 ? "" : "s"}`,
-      );
-    }
+    const totalChanges = addedKeys.length + removedKeys.length;
+    outro(
+      chalk.blue(
+        `Found ${totalChanges} translation key${totalChanges === 1 ? "" : "s"} changed`,
+      ),
+    );
 
-    outro(message);
     return {
-      addedKeys: Array.from(addedKeys),
-      removedKeys: Array.from(removedKeys),
+      addedKeys,
+      removedKeys,
     };
   } catch (error) {
     outro(chalk.red("Failed to check for changes"));

packages/cli/src/commands/translate.ts

@@ -1,3 +1,4 @@
+import { execSync } from "node:child_process";
 import fs from "node:fs/promises";
 import path from "node:path";
 import { createOpenAI } from "@ai-sdk/openai";
@@ -6,7 +7,7 @@ import { generateText } from "ai";
 import chalk from "chalk";
 import dedent from "dedent";
 import { prompt as defaultPrompt } from "../prompt.js";
-import { getApiKey, getConfig } from "../utils.js";
+import { extractChangedKeys, getApiKey, getConfig } from "../utils.js";
 
 export async function translate(targetLocale?: string) {
   intro("Starting translation process...");
@@ -32,7 +33,7 @@ export async function translate(targetLocale?: string) {
   });
 
   const s = spinner();
-  s.start("Translating to all target locales...");
+  s.start("Checking for changes and translating to target locales...");
 
   // Create translation tasks for all locales and file patterns
   const translationTasks = locales.flatMap((locale) =>
@@ -42,38 +43,66 @@ export async function translate(targetLocale?: string) {
         const targetPath = pattern.replace("[locale]", locale);
 
         try {
-          // Read source file
-          let sourceContent = "";
+          // Get git diff for source file
+          const diff = execSync(`git diff HEAD -- ${sourcePath}`, {
+            encoding: "utf-8",
+          });
+
+          if (!diff) {
+            return { locale, sourcePath, success: true, noChanges: true };
+          }
+
+          const { addedKeys } = extractChangedKeys(diff);
+
+          if (addedKeys.length === 0) {
+            return { locale, sourcePath, success: true, noChanges: true };
+          }
+
+          // Read source and target files
+          const sourceContent = await fs.readFile(
+            path.join(process.cwd(), sourcePath),
+            "utf-8",
+          );
+
+          let targetContent = "";
           try {
-            sourceContent = await fs.readFile(
-              path.join(process.cwd(), sourcePath),
+            targetContent = await fs.readFile(
+              path.join(process.cwd(), targetPath),
               "utf-8",
             );
           } catch (error) {
-            // Create source file if it doesn't exist
-            const sourceDir = path.dirname(
-              path.join(process.cwd(), sourcePath),
-            );
-            await fs.mkdir(sourceDir, { recursive: true });
-            await fs.writeFile(
-              path.join(process.cwd(), sourcePath),
-              "",
-              "utf-8",
+            // Create target file if it doesn't exist
+            const targetDir = path.dirname(
+              path.join(process.cwd(), targetPath),
             );
+            await fs.mkdir(targetDir, { recursive: true });
+          }
+
+          // Prepare translation prompt with only new keys
+          const sourceObj =
+            format === "ts"
+              ? Function(
+                  `return ${sourceContent.replace(/export default |as const;/g, "")}`,
+                )()
+              : JSON.parse(sourceContent);
+
+          const newKeysObj: Record<string, string> = {};
+          for (const key of addedKeys) {
+            newKeysObj[key] = sourceObj[key];
           }
 
-          // Prepare translation prompt
           const prompt = dedent`
             You are a professional translator working with ${format.toUpperCase()} files.
             
             Task: Translate the content below from ${source} to ${locale}.
+            Only translate the new keys provided.
 
             ${defaultPrompt}
 
             ${config.instructions ?? ""}
 
-            Source content:
-            ${sourceContent}
+            Source content (new keys only):
+            ${JSON.stringify(newKeysObj, null, 2)}
 
             Return only the translated content with identical structure.
           `;
@@ -84,27 +113,45 @@ export async function translate(targetLocale?: string) {
             prompt,
           });
 
+          // Parse the translated content
+          const translatedObj =
+            format === "ts"
+              ? Function(`return ${text.replace(/as const;?/g, "")}`)()
+              : JSON.parse(text);
+
+          // Merge with existing translations
+          const existingObj = targetContent
+            ? format === "ts"
+              ? Function(
+                  `return ${targetContent.replace(/export default |as const;/g, "")}`,
+                )()
+              : JSON.parse(targetContent)
+            : {};
+
+          const mergedObj = { ...existingObj, ...translatedObj };
+
+          // Format the final content
+          let finalContent =
+            format === "ts"
+              ? `export default ${JSON.stringify(mergedObj, null, 2)} as const;\n`
+              : JSON.stringify(mergedObj, null, 2);
+
           // Run afterTranslate hook if defined
-          let finalContent = text;
           if (config.hooks?.afterTranslate) {
             finalContent = await config.hooks.afterTranslate({
-              content: text,
+              content: finalContent,
               filePath: targetPath,
             });
           }
 
-          // Ensure target directory exists
-          const targetDir = path.dirname(path.join(process.cwd(), targetPath));
-          await fs.mkdir(targetDir, { recursive: true });
-
           // Write translated content
           await fs.writeFile(
             path.join(process.cwd(), targetPath),
             finalContent,
             "utf-8",
           );
 
-          return { locale, sourcePath, success: true };
+          return { locale, sourcePath, success: true, addedKeys };
         } catch (error) {
           return { locale, sourcePath, success: false, error };
         }
@@ -117,9 +164,23 @@ export async function translate(targetLocale?: string) {
 
   // Process results
   const failures = results.filter((r) => !r.success);
+  const changes = results.filter((r) => !r.noChanges && r.success);
+
+  s.stop("Translation completed");
+
+  if (changes.length > 0) {
+    for (const result of changes) {
+      console.log(
+        chalk.green(
+          `✓ Translated ${result.addedKeys?.length} new keys for ${result.locale}`,
+        ),
+      );
+    }
+  } else {
+    console.log(chalk.yellow("No new keys to translate"));
+  }
 
   if (failures.length > 0) {
-    s.stop("Translation completed with errors");
     for (const failure of failures) {
       console.error(
         chalk.red(
@@ -128,8 +189,6 @@ export async function translate(targetLocale?: string) {
         failure.error,
       );
     }
-  } else {
-    s.stop("Translation completed successfully");
   }
 
   outro(

packages/cli/src/utils.ts

@@ -77,3 +77,31 @@ export async function getConfig() {
 
   return config;
 }
+
+export function extractChangedKeys(diff: string) {
+  const addedKeys = new Set<string>();
+  const removedKeys = new Set<string>();
+
+  for (const line of diff.split("\n")) {
+    if (line.startsWith("+") && !line.startsWith("+++")) {
+      const match = line.match(/['"]([\w_.]+)['"]/);
+      if (match) addedKeys.add(match[1]);
+    } else if (line.startsWith("-") && !line.startsWith("---")) {
+      const match = line.match(/['"]([\w_.]+)['"]/);
+      if (match) removedKeys.add(match[1]);
+    }
+  }
+
+  // Remove keys that appear in both added and removed (these are modifications)
+  for (const key of addedKeys) {
+    if (removedKeys.has(key)) {
+      addedKeys.delete(key);
+      removedKeys.delete(key);
+    }
+  }
+
+  return {
+    addedKeys: Array.from(addedKeys),
+    removedKeys: Array.from(removedKeys),
+  };
+}