Interface: IUiChunkWriter

Defined in: entries/vercel-ui/types.ts:167

The chunks of one streamed answer, in the order the client expects: the chunk protocol has an order the gateway's events do not have (text-start before the first delta, text-end before a tool or the end).

Created by UiMapper.createChunkWriter, one per call; driven by AIGatewayVercelUi or by an application on its own transport.

Methods

onError()

onError(args): TGatewayUiChunk[]

Defined in: entries/vercel-ui/types.ts:232

onError -- the chunks that close the stream after a thrown error

About

error with the public reason, then finish; the open text and step closed first.

Who needs it

streamChunks of AIGatewayVercelUi, when the events or the response throw once the stream runs (toPublicError gives the reason: a 5xx never carries its message).

Parameters

args

reason

string

Returns

TGatewayUiChunk[]

---

onEvent()

onEvent(args): TGatewayUiChunk[]

Defined in: entries/vercel-ui/types.ts:202

onEvent -- the chunks of one event of the running call

About

Zero or more chunks, in the order the client's reducer expects.

A text delta opens its step and its text when they are not open; a tool request closes the text first; a step end closes both. RUN_ENDED_BY_TOOL and ANSWER_WITHDRAWN land as message-metadata; the other events add nothing, the response carries the result.

Who needs it

streamChunks of AIGatewayVercelUi, once per event of IGatewayCall.events (D38).

Pitfalls

Events in order, one writer per call: the writer keeps the open text and the open step between the calls.

Parameters

args

event

ILLMClientEvent

Returns

TGatewayUiChunk[]

---

onResponse()

onResponse(args): TGatewayUiChunk[]

Defined in: entries/vercel-ui/types.ts:219

onResponse -- the chunks that close the stream with the call's response

About

ANSWER, PAUSED or FAILED: the results as metadata, then finish.

ANSWER: message-metadata with the thread, usage, citations, issues, structured and endedByTool, then finish. PAUSED: a tool-approval-request per TOOL_APPROVAL envelope, the pause as metadata, finish. FAILED: an error chunk with the reason and a finish whose metadata carries the thread and the issues. The open text and step are closed first.

Who needs it

streamChunks of AIGatewayVercelUi, after the last event, with the awaited IGatewayCall.response.

Parameters

args

response

TGatewayResponse

Returns

TGatewayUiChunk[]

---

start()

start(): TGatewayUiChunk[]

Defined in: entries/vercel-ui/types.ts:182

start -- the chunks that open the stream

About

One start chunk: the message id, the date, the thread when it exists.

Called once, before the first event. A new thread's id is not known yet: it reaches the client with the response's metadata.

Who needs it

streamChunks of AIGatewayVercelUi, first thing; an application streaming on its own transport.

Returns

TGatewayUiChunk[]