Streaming Partial streams

Partial streams

connectPartialStream is for sources where a single row grows over time, like token-streamed assistant replies.

Use connectPartialStream when a single row grows over time. The canonical case: an assistant chat row whose content field accumulates token by token; tokens and latencyMs updated each chunk.

Signature

function connectPartialStream<
  TRow extends Record<string, unknown> & { id: string },
>(
  grid: GridLike<TRow>,
  stream: AsyncIterable<Partial<TRow>>,
  options: PartialStreamOptions,
): StreamConnection;
 
interface PartialStreamOptions {
  rowId: string;
}

Each yielded Partial<TRow> is merged into the row keyed by options.rowId via applyTransaction.update. The row must already exist (call applyTransaction.add once before connecting, or seed it through your engine state).

Recipe — chat completion

tsx

import { connectPartialStream } from "@pretable/stream-adapter";
 
// Seed the row first.
grid.applyTransaction({
  add: [
    { id: "msg-001", role: "assistant", content: "", tokens: 0, latencyMs: 0 },
  ],
});
 
connectPartialStream<ChatRow>(
  grid,
  openai.responses.stream({ model: "gpt-5", input: prompt }),
  { rowId: "msg-001" },
);

Each chunk's Partial<ChatRow> (whatever fields it carries — typically content deltas accumulated client-side) is merged into the seeded row. The grid's selection, scroll position, and focus state stay anchored to that row across every patch.

Lifecycle

Same as connectElementStream — done resolves when the iterator finishes, dispose() stops consuming early.

When you have raw JSON

If your source emits raw JSON strings (e.g. a single object whose keys arrive over time), pipe through parsePartialStream first. See Parsers →.