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 ();