PyNetworkTables2Js Client for Webpack projects

networkTables.js

import {encode, decode} from 'cbor-js';

export default class NetworkTables {
    _pynetworktables2jsAddress;

    constructor(pynetworktables2jsAddress) {
        this._pynetworktables2jsAddress = pynetworktables2jsAddress;
    }

    /**
     * the active connection to the pynetworktables2js server
     * @type {WebSocket || null}
     * @private
     */
    _socket = null;
    _socketConnectionListeners = new Set();

    addConnectionListener(listener, immediateNotify = true) {
        this._socketConnectionListeners.add(listener);
        if (immediateNotify) {
            listener(this._socket !== null && this._socket.readyState === WebSocket.OPEN);
        }

        return () => this._socketConnectionListeners.delete(listener);
    }

    robotAddress = null;
    _robotConnectionListeners = new Set();

    addRobotConnectionListener(listener, immediateNotify = true) {
        this._robotConnectionListeners.add(listener);
        if (immediateNotify) {
            listener(this._robotAddress);
        }

        return () => this._robotConnectionListeners.delete(listener);
    }

    table = new Map();
    _globalUpdateListeners = new Set();

    addGlobalUpdateListener(listener, immediateNotify = true) {
        this._globalUpdateListeners.add(listener);

        if (immediateNotify) {
            this.table.forEach((value, key) => listener(key, value, true));
        }

        return () => this._globalUpdateListeners.delete(listener);
    }

    connect() {
        const socket = this._socket = new WebSocket(`${this._pynetworktables2jsAddress}/networktables/ws`);
        socket.binaryType = "arraybuffer";
        socket.addEventListener("open", () => {
            console.info(`Connected to pynetworktables2js server at ${this._pynetworktables2jsAddress}`);
            this._socketConnectionListeners.forEach(it => it(true));
        });
        socket.addEventListener("message", message => {
            const data = decode(message.data);
            if (data.r) {
                this._robotConnectionListeners.forEach(it => it(this._robotAddress = data.a || null));
            } else {
                const key = data.k;
                const value = data.v;
                const isNew = data.n;

                this.table.set(key, value);
                this._globalUpdateListeners.forEach(listener => listener(key, value, isNew));
            }
        });
        socket.addEventListener("close", () => {
            console.info(`Connection to pynetworktables2js server closed`);

            this._robotConnectionListeners.forEach(it => it(null));
            this._socketConnectionListeners.forEach(it => it(false));
        });
        socket.addEventListener("error", () => {
            console.error(`An error occurred with the connection to ${this._pynetworktables2jsAddress}`);

            this._robotConnectionListeners.forEach(it => it(null));
            this._socketConnectionListeners.forEach(it => it(false));
        });
    }

    set(key, value) {
        this._socket.send(encode({
            k: key,
            v: value
        }));
    }
}