toDataStream + createHaloStream

Stream utilities for SSE protocol conversion and custom streaming.

Import

import { toDataStream, createHaloStream } from "@halo-ai/stream";

toDataStream(source, opts?)

Wraps an AsyncGenerator<TurnChunk> as an SSE Response. Compatible with Vercel AI SDK's useChat.

toDataStream(
  source: AsyncGenerator<TurnChunk>,
  opts?: { headers?: Record<string, string> }
): Response

SSE Protocol

TurnChunk	SSE Output
text-delta	0:"<delta>"
tool-call-delta	9:[<chunk>]
tool-call-ready	9:[<chunk>]
done	d:{"usage":{...}}

Usage

// In a Next.js API route
const stream = agent.sdkStream(messages);
return toDataStream(stream);

createHaloStream(fn)

Custom stream entry without going through HaloAgent.

createHaloStream(
  fn: (ctrl: {
    writeText: (delta: string) => void;
    writeToolCall: (call: ToolCall) => void;
    close: (usage?: Usage) => void;
    error: (err: Error) => void;
  }) => Promise<void>
): ReadableStream

Usage

const stream = createHaloStream(async (ctrl) => {
  ctrl.writeText("Processing... ");
  await someAsyncWork();
  ctrl.writeText("Done!");
  ctrl.close({ promptTokens: 10, completionTokens: 5 });
});