Avoid bad language pair problem.

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@samchon/json-translator",
-  "version": "2.1.2",
+  "version": "2.1.3",
   "description": "JSON Translator via Google Translation API with optimization strategies",
   "main": "lib/index.js",
   "types": "lib/index.d.ts",

src/JsonTranslator.ts

@@ -58,14 +58,26 @@ export class JsonTranslator {
     let bytes: number = 0;
     const execute = async () => {
       if (queue.length) {
-        const [response] = await this.service_.translate(
-          queue.map((p) => p.text),
-          {
-            from,
-            to: props.target,
-            format: "html",
-          },
-        );
+        const complete = (texts: string[]) => {
+          translated.push(...texts);
+          queue = [];
+          bytes = 0;
+        };
+        let response: string[] = [];
+        try {
+          [response] = await this.service_.translate(
+            queue.map((p) => p.text),
+            {
+              from,
+              to: props.target,
+              format: "html",
+            },
+          );
+        } catch (exp) {
+          if (exp instanceof Error && exp.message.includes("Bad language pair"))
+            return complete(queue.map((p) => p.text));
+          throw exp;
+        }
         const expected: number = queue
           .map((p) => p.text.split(SEPARATOR).length)
           .reduce((x, y) => x + y, 0);
@@ -88,10 +100,8 @@ export class JsonTranslator {
             `Mismatched translation count. Delivered ${expected} count string values to the Google Translate API, but received number is ${actual}.`,
           );
         }
-        translated.push(...response);
+        return complete(response);
       }
-      queue = [];
-      bytes = 0;
     };
 
     for (const text of collection.raw) {

test/features/test_bad_language_pair.ts

@@ -0,0 +1,26 @@
+import { TestValidator } from "@nestia/e2e";
+import { JsonTranslator } from "@samchon/json-translator";
+import typia, { tags } from "typia";
+
+import input from "../../assets/input/bbs.article.json";
+
+export const test_bad_language_pair = async (
+  translator: JsonTranslator,
+): Promise<void> => {
+  typia.assertGuard<IBbsArticle>(input);
+
+  const output: IBbsArticle = await translator.translate({
+    input,
+    target: "en",
+    filter: ({ key }) => key === "title" || key === "body",
+  });
+  TestValidator.equals("english to english")(input)(output);
+};
+
+interface IBbsArticle {
+  id: string & tags.Format<"uuid">;
+  title: string;
+  body: string;
+  created_at: string & tags.Format<"date-time">;
+  updated_at: string & tags.Format<"date-time">;
+}