@tasfer/provider-core

The transport-agnostic sync protocol behind every @tasfer/editor provider. Pair a CRDT Doc with a pipe and the two replicas converge: version vectors are exchanged, missing operations are sent, and new ones stream in real time after catch-up.

Most apps never import this directly — they install a transport package (@tasfer/provider-webrtc, @tasfer/provider-relay) that wraps it. Reach for it when you want to sync over something of your own.

Install

npm install @tasfer/editor @tasfer/provider-core

Usage

import { createProvider } from "@tasfer/provider-core";

const provider = createProvider({ doc: editor.doc, transport });

provider.on("sync", ({ connected, peers }) => {
  status.textContent = connected ? `${peers} peer(s)` : "offline";
});

Bring your own transport

A transport only has to discover peers and move opaque bytes between them. Implement Transport and you can sync over a relay, a BroadcastChannel, a file watcher, or your own backend:

interface Transport {
  connect(): Promise<void> | void;
  onPeerJoin(cb: (peer: TransportPeer) => void): () => void;
  onPeerLeave(cb: (peerId: string) => void): () => void;
  getPeers(): TransportPeer[];
  destroy(): void;
}

Each TransportPeer exposes send(bytes), onMessage(cb), and onClose(cb). Framing is the transport's problem; ordering and losslessness are its contract.

createBroadcastChannelTransport ships in the box — same-origin tab-to-tab sync, and a working reference implementation to read.

Presence

Presence is ephemeral state that travels alongside the document but is never persisted. The protocol routes whatever object you publish:

provider.presence.set({ name: "Ada", color: "#1db984" });

provider.presence.on("change", (peers) => {
  avatars.render(peers.map((p) => p.state.name));
});

To turn presence into remote carets and selections, bind it to the editor with the helper from the /cursors subpath — kept out of the base entry so a non-editor consumer of the protocol pays no editor coupling:

import { bindPresenceCursors } from "@tasfer/provider-core/cursors";

const stop = bindPresenceCursors(editor, provider, {
  user: { peerId, name: "Ada", color: "#1db984" },
});

Documentation

tasfer.app/docs/editor/collaboration

License

MIT