Binance Fetch Ohlcv Many Symbols Promise Then Callbacks

'use strict';

const ccxt = require ('../../js/ccxt.js')

console.log('CCXT Version:', ccxt.version)

function symbolLoop (exchange, symbol, timeframe) {
   exchange.fetchOHLCV (symbol, timeframe).then (ohlcvs => {
       console.log (exchange.iso8601 (exchange.milliseconds ()), exchange.id, symbol, ohlcvs.length, 'OHLCV candles received')
       setTimeout (() => symbolLoop (exchange, symbol, timeframe), 0)
   }).catch (e => {
       console.log (exchange.iso8601 (exchange.milliseconds ()), exchange.id, symbol, e.constructor.name, e.message)
       setTimeout (() => symbolLoop (exchange, symbol, timeframe), 0)
   })
}

function main () {
   const exchange = new ccxt.binance ()
   // exchange.verbose = true // uncomment for debugging purposes if necessary
   const symbols = [
       'BTC/USDT', // unified symbols used here as opposed to exchange-specific market ids
       'ETH/USDT', // more about unified symbols vs exchange-specific ids here:
       'ADA/USDT', // https://github.com/ccxt/ccxt/wiki/Manual#markets
   ]
   const timeframe = '1m'
   exchange.loadMarkets ().then (markets => {
       for (const symbol of symbols) {
           setTimeout (() => symbolLoop (exchange, symbol, timeframe), 0)
       }
   })
}

main ()