feat: return translation not supported error to the frontend

src/controllers/api/translate.ts

@@ -132,7 +132,10 @@ const translateController: AppController = async (c) => {
 
     dittoTranslations.set(translatedId, { data: mastodonTranslation });
     return c.json(mastodonTranslation, 200);
-  } catch {
+  } catch (e: any) {
+    if (e.message?.includes('not supported') || e.error?.includes('not supported')) {
+      return c.json({ error: `Translation of source language '${event.language}' not supported` }, 422);
+    }
     return c.json({ error: 'Service Unavailable' }, 503);
   }
 };

src/translators/DeepLTranslator.ts

@@ -68,6 +68,9 @@ export class DeepLTranslator implements DittoTranslator {
 
     const response = await this.fetch(request);
     const json = await response.json();
+    if (!response.ok) {
+      throw json;
+    }
     const data = DeepLTranslator.schema().parse(json);
 
     return data;

src/translators/LibreTranslateTranslator.ts

@@ -68,6 +68,9 @@ export class LibreTranslateTranslator implements DittoTranslator {
 
     const response = await this.fetch(request);
     const json = await response.json();
+    if (!response.ok) {
+      throw json;
+    }
     const data = LibreTranslateTranslator.schema().parse(json);
 
     return data;