Aggregate Function

1import { type Writer } from "./core.js";
2
3/**
4 * Inverse of `readAggregateFunction`: an `AggregateFunction(func, T…)` column is
5 * OPAQUE, unframed aggregation state with a layout specific to `func` and the
6 * server version, so it cannot be produced generically from a value. Build the
7 * state server-side (the `-State` combinators) rather than encoding it on the
8 * client.
9 *
10 * This writer throws to stop a generic encoder from emitting a misaligned row.
11 */
12export const writeAggregateFunction: Writer<never> = () => {
13  throw new Error(
14    "RowBinary: AggregateFunction is opaque, unframed aggregation state with no " +
15      "length prefix — not generically encodable. Produce the state server-side " +
16      "(the -State combinators) instead of encoding it on the client.",
17  );
18};