Streaming Parsers

Parsers

Lower-level parse* helpers if you need to feed the engine yourself.

The parse* helpers sit one layer below connect*. They accept an AsyncIterable<string> (raw JSON chunks from fetch, Response.body, SSE, etc.) and yield typed values. Pipe their output into the connect helpers.

`parseElementStream<TRow>(stream)`

Source emits a streaming JSON array. The parser yields each element as it parses — you don't wait for the array to close.

import { parseElementStream } from "@pretable/stream-adapter";
 
const res = await fetch("/api/events");
for await (const row of parseElementStream<Row>(res.body)) {
  console.log("got row", row);
}

In the connect-element pattern:

import {
  connectElementStream,
  parseElementStream,
} from "@pretable/stream-adapter";
 
const res = await fetch("/api/events");
connectElementStream<Row>(grid, parseElementStream<Row>(res.body));

`parsePartialStream<TRow>(stream)`

Source emits a streaming JSON object. The parser yields successive Partial<TRow> snapshots as keys complete.

import { parsePartialStream } from "@pretable/stream-adapter";
 
const res = await fetch("/api/single-row-events");
for await (const partial of parsePartialStream<Row>(res.body)) {
  console.log("snapshot so far", partial);
}

In the connect-partial pattern:

import {
  connectPartialStream,
  parsePartialStream,
} from "@pretable/stream-adapter";
 
const res = await fetch("/api/single-row-events");
connectPartialStream<Row>(grid, parsePartialStream<Row>(res.body), {
  rowId: "row-001",
});

Errors

Both parsers throw on malformed JSON. Wrap the consumer (or the connect call) in a try/catch and inspect via the done promise:

const conn = connectElementStream(grid, parseElementStream(res.body));
conn.done.catch((err) => console.error("stream failed:", err));