@flok-editor/pubsub

WebSocket-based Pub/Sub client and server, used for remote code execution and
message passing in Flok.

Features

- Basic Publish/Subscribe functionality: subscribe, unsubscribe, publish,
unsubscribeAll.
- Payload is JSON serialized, topics are any string.
- Allows subscribing or unsubscribing without being connected by storing state
on the client.
- Automatically reconnects if connection is lost, recovering client's state.
- Ping/pong mechanism for detecting and closing broken connections both on
client and server.

Usage

$3

``js
import { WebSocketServer } from "ws";
import { PubSubServer } from "@flok-editor/pubsub";

// To use the server, you need to create a WebSocketServer and pass it to
// PubSubServer.
const wss = new WebSocketServer({ port: 4000 });
const server = new PubSubServer({ wss });

console.log(PubSub server listening on, wss.address());
`

$3

`js
import { PubSubClient } from "@flok-editor/pubsub";

const client = new PubSubClient({ url: "ws://localhost:4000" });

// Subscribe to topics
client.subscribe("b");
client.subscribe("a");

client.start();

// Wait for the connection to be made, otherwise published messages are discarded.
let internalId;
client.on("open", () => {
// Publish a message (any JSON serializable object) to a topic
internalId = setInterval(() => {
client.publish("a", { salutation: "hello!" });
}, 2000);
});

// Add an error event handler to ignore connection errors
client.on("error", () => {});

client.on("close", () => clearInterval(internalId));

setTimeout(() => {
// Unsubscribe from a topic
client.unsubscribe("b");
// ... or from all topics with a single call
client.unsubscribeAll();
}, 5000);

// you can add a listener for all message events
client.on("message", (topic, data) => {
console.log("message", topic, data);
});

// ...or only from a specific topic
client.on("message:a", (data) => {
console.log("message from topic 'a'", data);
});

// Finally, you can subscribe and listen to messages in a single call
client.subscribe("c", (data) => {
console.log("message from 'c'", data);
});
`

Development

Run npm install to install dependencies.

Run npm run build` to build package.