@plim/transports

Tiny, generic duplex-channel primitives for the Plim block editor — and anything else that needs to move JSON-safe messages over a wire.

A Transport<T> is the smallest useful abstraction over a two-way message channel:

interface Transport<T> {
  send(message: T): void;
  onMessage(handler: (message: T) => void): () => void;
  close(): void;
}

Everything in Plim that syncs — real-time collaboration, comment threads, presence — is written against this one interface, so you can swap the wire (in-process, cross-tab, WebSocket, WebRTC, your own) without touching the feature code.

Install

pnpm add @plim/transports

What's in the box

• createMemoryTransportPair<T>() — two linked in-process transports (A↔B). Great for two-party tests and embedding.
• MemoryBus<T> — an in-process broadcast hub; every connect() returns a Transport<T> and a message from one peer is delivered to all the others (never echoed to the sender). Mirrors BroadcastChannel semantics for N peers in one process.
• BroadcastChannelTransport<T> — sync across same-origin browser tabs/workers via the native BroadcastChannel API.
• WebSocketTransport<T> — a reconnecting JSON WebSocket client. Buffers sends while offline, flushes on (re)connect, exponential backoff, and an onStatus hook. Works in the browser and in Node (pass a WebSocket implementation).
• mapTransport(inner, encode, decode) — adapt a Transport<A> into a Transport<B> with a codec (e.g. wrap/compress/namespace messages).

Where to go next

• Collaboration — @plim/collaboration syncs over these transports.
• Persistence — @plim/storage's createTransportAdapter saves through one.
• Sync log — @plim/ledger.

License

See the LICENSE file in this package.