feat(js/plugins/google-genai): Added Gemini for VertexAI (#3121)

Author: ifielker

js/plugins/google-genai/src/googleai/gemini.ts

@@ -276,7 +276,7 @@ export type GeminiVersionString =
  * ```js
  * await ai.generate({
  *   prompt: 'hi',
- *   model: gemini('gemini-1.5-flash')
+ *   model: gemini('gemini-2.5-flash')
  * });
  * ```
  */

js/plugins/google-genai/src/vertexai/converters.ts

@@ -0,0 +1,35 @@
+/**
+ * Copyright 2025 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { z } from 'genkit';
+import {
+  HarmBlockThreshold,
+  HarmCategory,
+  SafetySetting,
+} from '../common/types';
+import { SafetySettingsSchema } from './gemini';
+
+export function toGeminiSafetySettings(
+  genkitSettings?: z.infer<typeof SafetySettingsSchema>[]
+): SafetySetting[] | undefined {
+  if (!genkitSettings) return undefined;
+  return genkitSettings.map((s) => {
+    return {
+      category: s.category as HarmCategory,
+      threshold: s.threshold as HarmBlockThreshold,
+    };
+  });
+}