interface ChannelOptions

How a Channel behaves when its consumer cannot keep up.

const options: ChannelOptions<number> = { capacity: 1_000, overflow: 'dropNewest' };
options.capacity; // 1000 — past this, `overflow` decides which element is lost

Type Parameters

E = never

Properties

optional
capacity: number

How many elements to buffer for a consumer that has not taken them yet. Default 10_000.

optional
overflow: Overflow

What to do once capacity is reached: drop from either end, or 'fail' — end the stream with a ChannelOverflowFailure element instead of losing anything quietly. Default 'dropOldest'.

optional
onDiscard: (
dropped: T | E,
buffered: number
) => void

Called with each element the buffer actually lost, and the depth after the loss. The only place overflow is observable — make it fatal from here by calling fail or abort.

optional
onDemand: () => void

Called once, when a consumer first attaches. A producer that can defer starting should start here: it is the difference between a buffer that stays near empty and one that races ahead of a consumer that has not arrived.

Usage

import { type ChannelOptions } from "lib/stream/index.ts";