Poll Ohlcv

import ccxt from '../../js/ccxt.js';

const ohlcvsBySymbol = {}

function handleAllOHLCVs (exchange, ohlcvs, symbol, timeframe) {
   console.log ('----------------------------------------------------------')
   console.log ('Last updated:', exchange.iso8601 (exchange.milliseconds ()))
   const symbols = Object.keys (ohlcvsBySymbol)
   for (let i = 0; i < symbols.length; i++) {
       const symbol = symbols[i]
       const ohlcvs = ohlcvsBySymbol[symbol]
       const lastCandle = exchange.safeValue (ohlcvs, ohlcvs.length - 1)
       const lastTimestamp = lastCandle[0]
       console.log (exchange.iso8601 (lastTimestamp), symbol, timeframe, lastCandle.slice (1))
   }
}

async function pollOHLCV (exchange, symbol, timeframe) {
   while (true) {
       try {
           const response = await exchange.fetchOHLCV (symbol, timeframe)
           ohlcvsBySymbol[symbol] = response
           handleAllOHLCVs(exchange, response, symbol, timeframe)
       } catch (e) {
           console.log (e.constructor.name, e.message)
       }
   }
}

async function main () {

   const exchange = new ccxt.binance()
   const markets = await exchange.loadMarkets ()
   const timeframe = '5m'

   const firstOneHundredSymbols = exchange.symbols.slice (0, 100)

   await Promise.all (firstOneHundredSymbols.map (symbol => pollOHLCV (exchange, symbol, timeframe)))
}

main ()