Websockets Depth Cache for Binance

depthcache.js

var WebSocket = require('ws');

var ws;

var depthCache = {}
function connect() {
    ws = new WebSocket("wss://fstream.binance.com/ws/bnbusdt@depth@0ms");
    ws.on('open', function open() {
        ws.send('something');
    });
    ws.on('connection', function incoming(data) {
        console.log("connected")
        console.log(data);
    });
    ws.on('ping', function incoming(data) {
        console.log("ping")
        console.log(data);
    });
    ws.on('pong', function incoming(data) {
        console.log("pong")
        console.log(data);
    });
    ws.on('close', function incoming(data) {
        console.log("closed")
        setTimeout(connect, 1000)
        console.log(data);
    });
    ws.on('message', function incoming(data) {
        console.log("message", data)
        try {
            data = JSON.parse(data)
            data.a.forEach(ask => {
                var price = ask[0]
                var volume = Number(ask[1])
                if (volume == 0) {
                    delete cache[price]
                } else {
                    cache[price] = volume
                }
            });
            data.b.forEach(ask => {
                var price = ask[0]
                var volume = Number(ask[1])
                if (volume == 0) {
                    delete cache[price]
                } else {
                    cache[price] = volume
                }
            });

           

        } catch (ex) {
            console.error("error", ex, data)
        }

    });
}
connect()
var cache = {}