Errors

The first error ends the iteration: the consumer receives the items that were already emitted, then the error is thrown from for await or toArray().

async function* failing() {
    yield 1;
    yield 2;
    throw new Error("source failed");
}

try {
    for await (const batch of chain(failing()).batch(5)) {
        console.log(batch);
    }
} catch (error) {
    console.log((error as Error).message);
}
// [ 1, 2 ]
// source failed

• map: an error thrown by the mapper is rethrown unless an error mapper turns it into a value.
• batch, interval, bufferize: the items accumulated at the moment of the failure are emitted first, as a last, smaller value.
• concurrentMap: after an error no new calls start, and the results of calls that are still running are discarded. Like map, it rethrows a mapper error unless an error mapper is given.
• mux: the first failing input ends the iteration; the other inputs stop at their next item. An input that is blocked while sending at that moment may stay blocked, because a blocked send is not woken up when the queue ends; it holds no CPU and raises no error.