Watch Many Exchanges Many Symbols

'use strict';

import ccxt from '../../js/ccxt.js';

console.log ('CCXT Version:', ccxt.version); // eslint-disable-line import/no-named-as-default-member

async function watchTickerLoop (exchange, symbol) {
    // exchange.verbose = true // uncomment for debugging purposes if necessary
    while (true) { // eslint-disable-line no-constant-condition
        try {
            const ticker = await exchange.watchTicker (symbol);
            console.log (new Date (), exchange.id, symbol, ticker['last']);
        } catch (e) {
            console.log (symbol, e);
            // do nothing and retry on next loop iteration
            // throw e // uncomment to break all loops in case of an error in any one of them
            // break // you can also break just this one loop if it fails
        }
    }
}

async function exchangeLoop (exchangeId, symbols) {
    const exchange = new ccxt.pro[exchangeId] (); // eslint-disable-line import/no-named-as-default-member
    await exchange.loadMarkets ();
    const loops = symbols.map ((symbol) => watchTickerLoop (exchange, symbol));
    await Promise.all (loops);
    await exchange.close ();
}

async function main () {
    const exchanges = {
        'binance': [ 'BTC/USDT', 'ETH/USDT' ],
        'okx': [ 'BTC/USD', 'ETH/USD' ],
    };
    const loops = Object.entries (exchanges).map (([ exchangeId, symbols ]) => exchangeLoop (exchangeId, symbols));
    await Promise.all (loops);
}

main ();