@atlaskit/editor-plugin-collab-edit
Version:
Collab Edit plugin for @atlaskit/editor-core
52 lines (51 loc) • 2.84 kB
TypeScript
import type { Transaction } from '@atlaskit/editor-prosemirror/state';
/**
* Upper bound on how long the send may stay held, measured from the transaction that *started* the
* hold rather than the most recent one.
*
* This is the only time bound on the hold. Producers decide when to release on semantic grounds —
* a completed block, the end of a stream — and this bounds how long that can take. It therefore
* doubles as the guarantee that a producer which never releases, because it aborted or threw
* between hold and release, cannot stop the editor sending for the rest of the session.
*/
export declare const MAX_SEND_HOLD_MS = 2000;
export type CollabSendHold = {
/**
* Whether the flush is currently held. Reads the clock, so a hold that has outlived
* {@link MAX_SEND_HOLD_MS} reports as released without needing a transaction to clear it.
*/
isHeld: (now?: number) => boolean;
/**
* Feed every transaction through this. Transactions that carry no {@link DEFER_COLLAB_SEND}
* metadata leave the hold untouched — that is the whole point of the hold being sticky rather
* than per-transaction.
*/
observe: (transaction: Readonly<Transaction>, now?: number) => void;
};
/**
* Tracks whether sending to the collab service is currently held back.
*
* A producer that streams into the document needs several of its transactions to accumulate in the
* unconfirmed queue before anything is sent, so they can be composed into one step. Marking only
* the producer's own transactions is not enough: `sendTransaction` runs for *every* state update,
* and `provider.send` flushes and locks the entire queue regardless of which transaction triggered
* it. Acknowledgements from previous commits, remote steps, selection changes and the user's own
* typing all trigger it.
*
* So the hold has to be a state that spans transactions rather than a flag on one:
*
* - `tr.setMeta(DEFER_COLLAB_SEND, true)` starts the hold, and does *not* extend one already in
* progress
* - `tr.setMeta(DEFER_COLLAB_SEND, false)` releases it
* - anything else leaves it as it is
*
* Not extending matters. A producer marks every frame it wants held, so re-arming on each one
* would push the deadline back indefinitely and the bound would never be reached during an active
* stream. Measuring from the first held transaction instead makes the hold flush at least every
* {@link MAX_SEND_HOLD_MS}, with the next held frame starting a fresh window.
*
* While held, nothing is sent. Note this includes the local user's own edits: `sendableSteps`
* returns the queue in version order, so there is no way to send a step that sits behind held
* steps. Producers should keep hold windows short for that reason.
*/
export declare const createCollabSendHold: () => CollabSendHold;