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();