index.ts

/**
 * Vercel AI SDK transport wrappers that pre-bind the UIMessageCodec.
 *
 * These are convenience factories so consumers don't need to pass the codec
 * explicitly when using the Vercel AI SDK integration.
 *
 * ```ts
 * import { createClientTransport } from '@ably/ai-transport/vercel';
 *
 * const transport = createClientTransport({ channel });
 * ```
 */

// Chat transport adapter
export type { ChatTransport, ChatTransportOptions, SendMessagesRequestContext } from './chat-transport.js';
export { createChatTransport } from './chat-transport.js';

import type * as AI from 'ai';

import { createClientTransport as createCoreClientTransport } from '../../core/transport/client-transport.js';
import { createServerTransport as createCoreServerTransport } from '../../core/transport/server-transport.js';
import type {
  ClientTransport,
  ClientTransportOptions,
  ServerTransport,
  ServerTransportOptions,
} from '../../core/transport/types.js';
import { UIMessageCodec } from '../codec/index.js';

/** Core client transport options with Vercel AI SDK types pre-applied. */
type CoreClientOpts = ClientTransportOptions<AI.UIMessageChunk, AI.UIMessage>;

/** Options for creating a Vercel client transport. Same as core options but without the codec field, and with `api` optional (defaults to `"/api/chat"`). */
export type VercelClientTransportOptions = Omit<CoreClientOpts, 'codec' | 'api'> & Partial<Pick<CoreClientOpts, 'api'>>;

/** Options for creating a Vercel server transport. Same as core options but without the codec field. */
export type VercelServerTransportOptions = Omit<ServerTransportOptions<AI.UIMessageChunk, AI.UIMessage>, 'codec'>;

/**
 * Create a client-side transport pre-configured with the Vercel AI SDK codec.
 *
 * Equivalent to calling the core `createClientTransport` with `codec: UIMessageCodec`.
 * @param options - Configuration for the client transport (codec is provided automatically).
 * @returns A new {@link ClientTransport} for Vercel AI SDK UIMessage/UIMessageChunk types.
 */
export const createClientTransport = (
  options: VercelClientTransportOptions,
): ClientTransport<AI.UIMessageChunk, AI.UIMessage> =>
  createCoreClientTransport({
    ...options,
    codec: UIMessageCodec,
    // Mirrors the Vercel AI SDK's DefaultChatTransport default.
    api: options.api ?? '/api/chat',
  });

/**
 * Create a server-side transport pre-configured with the Vercel AI SDK codec.
 *
 * Equivalent to calling the core `createServerTransport` with `codec: UIMessageCodec`.
 * @param options - Configuration for the server transport (codec is provided automatically).
 * @returns A new {@link ServerTransport} for Vercel AI SDK UIMessage/UIMessageChunk types.
 */
export const createServerTransport = (
  options: VercelServerTransportOptions,
): ServerTransport<AI.UIMessageChunk, AI.UIMessage> => createCoreServerTransport({ ...options, codec: UIMessageCodec });