prosemirror-collab-commit

Commit-based collaborative editing plugin for ProseMirror.

This solves two key problems with prosemirror-collab through server-side rebasing without the use of CRDTs:

1. Throughput: 200 active clients per 1s of commit delay is feasible depending on backend implementation and edit characteristics.
2. Fairness: Users with high latencies will not have their edits blocked by users with low latencies. This will greatly smooth the collab experience on documents with high levels of concurrent edits.

How it works

The performance issues with prosemirror-collab and how this plugin solves them are written about in ProseMirror Collab Performance.

Usage

Abridged usage examples that should be familar to those who have used prosemirror-collab.

As with prosemirror-collab the actual backend implementation is left to the developer. TODO: Implement indicates code the implementor must write.

Client Send Commit

import { collab, sendableCommit } from "@stepwisehq/prosemirror-collab-commit/collab-commit"

const state = EditorState.create({schema}, {plugins: [collab()]})

//Some edits later...

const commit = sendableCommit(state)
await sendCommitToServer(commit.toJSON()) // TODO: Implement

Client Receive Commit

import { receiveCommitTransaction } from "@stepwisehq/prosemirror-collab-commit/collab-commit"

//...

const commitJson = await fetchNextCommitFromServer() // TODO: Implement
const commit = Commit.FromJSON(state.schema, commitJson)
const tr = receiveCommitTransaction(state, commit)
state = state.apply(tr)

Authority Map Commit

import { applyCommitJSON } from "@stepwisehq/prosemirror-collab-commit/apply-commit"

const newCommitJson = await getCommitsFromClient() // TODO: Implement

const version = await getDocumentVersion() // TODO: Implement
const doc = await getDocument() // TODO: Implement
const newCommits = await getDocumentCommitsSince(commitJson.version) // TODO: Implement
const schemaSpec = await getSchemaSpec() // TODO: Implement

const schema = new Schema(schemaSpec)

const {docJson, commitJson} = applyCommitJSON(version, schema, doc, newCommits, newCommitJson)

await saveDocument(docJson) // TODO: Implement
await broadcastCommit(commitJson) // TODO: Implement