feat: Add VercelAI Provider for AI SDK

package.json

@@ -2,6 +2,7 @@
   "name": "@launchdarkly/js-core",
   "workspaces": [
     "packages/ai-providers/server-ai-langchain",
+    "packages/ai-providers/server-ai-vercel",
     "packages/shared/common",
     "packages/shared/sdk-client",
     "packages/shared/sdk-server",

packages/ai-providers/server-ai-vercel/__tests__/VercelProvider.test.ts

@@ -0,0 +1,207 @@
+import { VercelProvider } from '../src/VercelProvider';
+
+// Mock Vercel AI SDK
+jest.mock('ai', () => ({
+  generateText: jest.fn(),
+}));
+
+describe('VercelProvider', () => {
+  let mockModel: any;
+  let provider: VercelProvider;
+
+  beforeEach(() => {
+    mockModel = { name: 'test-model' };
+    provider = new VercelProvider(mockModel, {});
+  });
+
+  describe('createAIMetrics', () => {
+    it('creates metrics with success=true and token usage', () => {
+      const mockResponse = {
+        usage: {
+          promptTokens: 50,
+          completionTokens: 50,
+          totalTokens: 100,
+        },
+      };
+
+      const result = VercelProvider.createAIMetrics(mockResponse);
+
+      expect(result).toEqual({
+        success: true,
+        usage: {
+          total: 100,
+          input: 50,
+          output: 50,
+        },
+      });
+    });
+
+    it('creates metrics with success=true and no usage when usage is missing', () => {
+      const mockResponse = {};
+
+      const result = VercelProvider.createAIMetrics(mockResponse);
+
+      expect(result).toEqual({
+        success: true,
+        usage: undefined,
+      });
+    });
+
+    it('handles partial usage data', () => {
+      const mockResponse = {
+        usage: {
+          promptTokens: 30,
+          // completionTokens and totalTokens missing
+        },
+      };
+
+      const result = VercelProvider.createAIMetrics(mockResponse);
+
+      expect(result).toEqual({
+        success: true,
+        usage: {
+          total: 0,
+          input: 30,
+          output: 0,
+        },
+      });
+    });
+  });
+
+  describe('invokeModel', () => {
+    it('invokes Vercel AI generateText and returns response', async () => {
+      const { generateText } = require('ai');
+      const mockResponse = {
+        text: 'Hello! How can I help you today?',
+        usage: {
+          promptTokens: 10,
+          completionTokens: 15,
+          totalTokens: 25,
+        },
+      };
+
+      (generateText as jest.Mock).mockResolvedValue(mockResponse);
+
+      const messages = [
+        { role: 'user' as const, content: 'Hello!' },
+      ];
+
+      const result = await provider.invokeModel(messages);
+
+      expect(generateText).toHaveBeenCalledWith({
+        model: mockModel,
+        messages: [{ role: 'user', content: 'Hello!' }],
+      });
+
+      expect(result).toEqual({
+        message: {
+          role: 'assistant',
+          content: 'Hello! How can I help you today?',
+        },
+        metrics: {
+          success: true,
+          usage: {
+            total: 25,
+            input: 10,
+            output: 15,
+          },
+        },
+      });
+    });
+
+    it('handles response without usage data', async () => {
+      const { generateText } = require('ai');
+      const mockResponse = {
+        text: 'Hello! How can I help you today?',
+      };
+
+      (generateText as jest.Mock).mockResolvedValue(mockResponse);
+
+      const messages = [
+        { role: 'user' as const, content: 'Hello!' },
+      ];
+
+      const result = await provider.invokeModel(messages);
+
+      expect(result).toEqual({
+        message: {
+          role: 'assistant',
+          content: 'Hello! How can I help you today?',
+        },
+        metrics: {
+          success: true,
+          usage: undefined,
+        },
+      });
+    });
+  });
+
+  describe('getModel', () => {
+    it('returns the underlying Vercel AI model', () => {
+      const model = provider.getModel();
+      expect(model).toBe(mockModel);
+    });
+  });
+
+  describe('createVercelModel', () => {
+    it('creates OpenAI model for openai provider', async () => {
+      const mockAiConfig = {
+        model: { name: 'gpt-4', parameters: {} },
+        provider: { name: 'openai' },
+        enabled: true,
+        tracker: {} as any,
+        toVercelAISDK: jest.fn(),
+      };
+
+      // Mock the dynamic import
+      jest.doMock('@ai-sdk/openai', () => ({
+        openai: jest.fn().mockReturnValue(mockModel),
+      }));
+
+      const result = await VercelProvider.createVercelModel(mockAiConfig);
+      expect(result).toBe(mockModel);
+    });
+
+    it('throws error for unsupported provider', async () => {
+      const mockAiConfig = {
+        model: { name: 'test-model', parameters: {} },
+        provider: { name: 'unsupported' },
+        enabled: true,
+        tracker: {} as any,
+        toVercelAISDK: jest.fn(),
+      };
+
+      await expect(VercelProvider.createVercelModel(mockAiConfig)).rejects.toThrow(
+        'Unsupported Vercel AI provider: unsupported'
+      );
+    });
+  });
+
+  describe('create', () => {
+    it('creates VercelProvider with correct model and parameters', async () => {
+      const mockAiConfig = {
+        model: {
+          name: 'gpt-4',
+          parameters: {
+            temperature: 0.7,
+            maxTokens: 1000,
+          },
+        },
+        provider: { name: 'openai' },
+        enabled: true,
+        tracker: {} as any,
+        toVercelAISDK: jest.fn(),
+      };
+
+      // Mock the dynamic import
+      jest.doMock('@ai-sdk/openai', () => ({
+        openai: jest.fn().mockReturnValue(mockModel),
+      }));
+
+      const result = await VercelProvider.create(mockAiConfig);
+
+      expect(result).toBeInstanceOf(VercelProvider);
+      expect(result.getModel()).toBeDefined();
+    });
+  });
+});

packages/ai-providers/server-ai-vercel/jest.config.js

@@ -0,0 +1,14 @@
+module.exports = {
+  preset: 'ts-jest',
+  testEnvironment: 'node',
+  roots: ['<rootDir>'],
+  testMatch: ['**/__tests__/**/*.test.ts'],
+  collectCoverageFrom: [
+    'src/**/*.ts',
+    '!src/**/*.d.ts',
+    '!src/**/*.test.ts',
+    '!src/**/*.spec.ts',
+  ],
+  coverageDirectory: 'coverage',
+  coverageReporters: ['text', 'lcov', 'html'],
+};

packages/ai-providers/server-ai-vercel/package.json

@@ -0,0 +1,67 @@
+{
+  "name": "@launchdarkly/server-sdk-ai-vercel",
+  "version": "0.0.0",
+  "description": "LaunchDarkly AI SDK Vercel Provider for Server-Side JavaScript",
+  "homepage": "https://github.com/launchdarkly/js-core/tree/main/packages/ai-providers/server-ai-vercel",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/launchdarkly/js-core.git"
+  },
+  "main": "dist/index.js",
+  "types": "dist/index.d.ts",
+  "type": "commonjs",
+  "scripts": {
+    "build": "npx tsc",
+    "lint": "npx eslint . --ext .ts",
+    "prettier": "prettier --write '**/*.@(js|ts|tsx|json|css)' --ignore-path ../../../.prettierignore",
+    "lint:fix": "yarn run lint --fix",
+    "check": "yarn prettier && yarn lint && yarn build && yarn test",
+    "test": "jest"
+  },
+  "keywords": [
+    "launchdarkly",
+    "ai",
+    "llm",
+    "vercel"
+  ],
+  "author": "LaunchDarkly",
+  "license": "Apache-2.0",
+  "dependencies": {
+    "@ai-sdk/provider": "^2.0.0",
+    "@launchdarkly/server-sdk-ai": "^0.12.0",
+    "ai": "^5.0.0"
+  },
+  "optionalDependencies": {
+    "@ai-sdk/anthropic": "^2.0.0",
+    "@ai-sdk/cohere": "^2.0.0",
+    "@ai-sdk/google": "^2.0.0",
+    "@ai-sdk/mistral": "^2.0.0",
+    "@ai-sdk/openai": "^2.0.0"
+  },
+  "devDependencies": {
+    "@ai-sdk/anthropic": "^2.0.0",
+    "@ai-sdk/cohere": "^2.0.0",
+    "@ai-sdk/google": "^2.0.0",
+    "@ai-sdk/mistral": "^2.0.0",
+    "@ai-sdk/openai": "^2.0.0",
+    "@launchdarkly/js-server-sdk-common": "2.16.2",
+    "@trivago/prettier-plugin-sort-imports": "^4.1.1",
+    "@types/jest": "^29.5.3",
+    "@typescript-eslint/eslint-plugin": "^6.20.0",
+    "@typescript-eslint/parser": "^6.20.0",
+    "eslint": "^8.45.0",
+    "eslint-config-airbnb-base": "^15.0.0",
+    "eslint-config-airbnb-typescript": "^17.1.0",
+    "eslint-config-prettier": "^8.8.0",
+    "eslint-plugin-import": "^2.27.5",
+    "eslint-plugin-jest": "^27.6.3",
+    "eslint-plugin-prettier": "^5.0.0",
+    "jest": "^29.6.1",
+    "prettier": "^3.0.0",
+    "ts-jest": "^29.1.1",
+    "typescript": "5.1.6"
+  },
+  "peerDependencies": {
+    "@launchdarkly/js-server-sdk-common": "2.x"
+  }
+}