Looping Over Specific Symbols Of All Exchanges

// @NO_AUTO_TRANSPILE
import ccxt from '../../js/ccxt.js';
import ololog from 'ololog';
import ansicolor from 'ansicolor';
const log = ololog.configure({ locate: false }), verbose = process.argv.includes('--verbose');
ansicolor.nice;
(async () => {
    const exchanges = {};
    const symbols = ['ETH/BTC', 'XRP/BTC', 'BTC/USDT'];
    for (let symbol of symbols) {
        for (let exchangeId of ccxt.exchanges) {
            let exchange = undefined;
            try { // try creating the exchange instance first and handle errors if any
                // check if we have created an instance of this exchange already
                exchange = exchanges[exchangeId];
                if (exchange === undefined) {
                    // create the exchange instance
                    exchange = new ccxt[exchangeId]();
                }
                exchanges[exchangeId] = exchange; // save it for later use
            }
            catch (e) {
                log.red('Could not create exchange', exchangeId + ':', e.constructor.name, e.message);
                // uncomment the following line to interrupt program execution on error
                // or leave it commented out to do nothing
                // process.exit ()
            }
            if (exchange !== undefined) {
                // preload all markets first, as explained in the Manual:
                // https://github.com/ccxt/ccxt/wiki/Manual#loading-markets
                // add error/exception handling as required by the Manual:
                // https://github.com/ccxt/ccxt/wiki/Manual#error-handling
                try {
                    await exchange.loadMarkets();
                }
                catch (e) {
                    log.red('Could not load markets from', exchange.id + ':', e.constructor.name, e.message);
                    continue; // skip this exchange if markets failed to load
                }
                for (let symbol of symbols) {
                    console.log(exchange.id, symbol);
                    // add error/exception handling as required by the Manual:
                    // https://github.com/ccxt/ccxt/wiki/Manual#error-handling
                    try { // try fetching the ticker for a symbol existing with that exchange
                        const ticker = await exchange.fetchTicker(symbol);
                        log.green(ticker);
                    }
                    catch (e) { // catch the error (if any) and handle it or ignore it
                        log.red('Could not fetch', symbol, 'ticker from', exchange.id + ':', e.constructor.name, e.message);
                    }
                }
            }
        }
    }
})();