Binance Watch Ohlcv 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
function handle(exchange, symbol, timeframe, candles) {
   const lastCandle = candles[candles.length - 1];
   const lastClosingPrice = lastCandle[4];
   console.log(new Date(), exchange.id, timeframe, symbol, '\t', lastClosingPrice);
}
async function loop(exchange, symbol, timeframe) {
   while (true) { // eslint-disable-line no-constant-condition
       try {
           const candles = await exchange.watchOHLCV(symbol, timeframe);
           handle(exchange, symbol, timeframe, candles);
       }
       catch (e) {
           console.log(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 main() {
   const exchange = new ccxt.pro.binance(); // eslint-disable-line import/no-named-as-default-member
   //
   // WARNING: when using all the markets mind subscription limits!
   // don't attempt to subscribe to all of them
   // the exchanges will not allow that in general
   // instead, specify a shorter list of symbols to subscribe to
   //
   if (exchange.has['watchOHLCV']) {
       await exchange.loadMarkets();
       const timeframe = '15m';
       // many symbols
       await Promise.all(exchange.symbols.map((symbol) => loop(exchange, symbol, timeframe)));
       //
       // or
       //
       // const symbols = [ 'BTC/USDT', 'ETH/USDT' ] // specific symbols
       // await Promise.all (symbols.map (symbol => loop (exchange, symbol, timeframe)))
       //
       // or
       //
       // await loop (exchange, 'BTC/USDT', timeframe) // one symbol
   }
   else {
       console.log(exchange.id, 'does not support watchOHLCV yet');
   }
}
main();