Fetch Ticker From Multiple Exchanges

import ccxt from '../../js/ccxt.js';
(async () => {

   const exchanges = [
       'bittrex',
       'poloniex',
   ]

   const symbol = 'BTC/USDT'
   const tickers = {}

   await Promise.all (exchanges.map (exchangeId =>

       new Promise (async (resolve, reject) => {

           const exchange = new ccxt[exchangeId] ()

           while (true) {

               const ticker = await exchange.fetchTicker (symbol)
               tickers[exchangeId] = ticker

               Object.keys (tickers).map (exchangeId => {
                   const ticker = tickers[exchangeId]
                   console.log (ticker['datetime'], exchangeId, ticker['bid'], ticker['ask'])
               })
           }

       })

   ))

}) ()