Binance Watch Ohlcv Many Symbols

'use strict';

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

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

async function loop (exchange, symbol, timeframe, i) {
    await exchange.throttle (1000 * i); // 1000ms delay between subscriptions
    while (true) {
        try {
            const candles = await exchange.watchOHLCV (symbol, timeframe);
            console.log ('do something with candles...', candles.length);
        } catch (e) {
            console.log (e); // do nothing and retry on next loop iteration
            // throw e // break all loops in case of an error in any one of them
            // break // silently break only this one loop
        }
    }
}

async function example () {
    const exchange = new ccxt.pro.binance ();
    //
    // WARNING: because of subscription limits, exchanges might not allow to subscribe
    // to all markets at once - better to specify a shorter list of symbols
    //
    if (exchange.has['watchOHLCV']) {
        await exchange.loadMarkets ();
        const timeframe = '15m';
        const mySymbols = [ 'BTC/USDT', 'ETH/USDT' ]; // or use "exchange.symbols" for all symbols
        const allPromises = [];
        for (let i = 0; i < mySymbols.length; i++) {
            allPromises.push (loop (exchange, mySymbols[i], timeframe, i));
        }
        await Promise.all (allPromises);
    } else {
        console.log (exchange.id, 'does not support watchOHLCV yet');
    }
}

example ();