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batch()

batch<T>(sizeOrOptions): OperatorFunction<T, T[]>

Defined in: src/Batch.ts:43

Creates an operator that groups items into arrays.

A number is a shortcut for the size option. A batch is emitted when it reaches size items or, if timeFrame is set, that many milliseconds after its first item. The remainder at the end of the source is emitted as a smaller batch.

If the source throws, the batch collected so far is emitted first and the error is thrown after it.

Type Parameters​

T​

T

Parameters​

sizeOrOptions​

number | BatchOptions

the batch size or BatchOptions

Returns​

OperatorFunction<T, T[]>

an operator function

Example​

await chain(range(0, 5)).batch(2).toArray();
// => [[0, 1], [2, 3], [4]]

import { setTimeout as sleep } from "node:timers/promises";

async function* slow() {
    yield 1;
    await sleep(150);
    yield 2;
}
await chain(slow()).batch({ size: 10, timeFrame: 50 }).toArray();
// => [[1], [2]]