Live Orderbook

import asTable from 'as-table';
import ololog from 'ololog';
import ansicolor from 'ansicolor';
import ccxt from '../../js/ccxt.js';

const { noLocate } = ololog;
const log = noLocate;

ansicolor.nice

let printSupportedExchanges = function () {
   log ('Supported exchanges:', ccxt.exchanges.join (', ').green)
}

let printUsage = function () {
   log ('Usage: node', process.argv[1], 'exchange'.green, 'symbol'.yellow, 'depth'.cyan)
   printSupportedExchanges ()
}

let printOrderBook = async (id, symbol, depth) => {

   // check if the exchange is supported by ccxt
   let exchangeFound = ccxt.exchanges.indexOf (id) > -1
   if (exchangeFound) {

       log ('Instantiating', id.green, 'exchange')

       // instantiate the exchange by id
       let exchange = new ccxt[id] ()

       // load all markets from the exchange
       let markets = await exchange.loadMarkets ()

       // output a list of all market symbols
       // log (id.green, 'has', exchange.symbols.length, 'symbols:', exchange.symbols.join (', ').yellow)

       if (symbol in exchange.markets) {

           const market = exchange.markets[symbol]
           const pricePrecision = market.precision ? market.precision.price : 8
           const amountPrecision = market.precision ? market.precision.amount : 8

           // Object.values (markets).forEach (market => log (market))

           // make a table of all markets
           // const table = asTable.configure ({ delimiter: ' | ' }) (Object.values (markets))
           // log (table)

           const priceVolumeHelper = color => ([price, amount]) => ({
               price: price.toFixed (pricePrecision)[color],
               amount: amount.toFixed (amountPrecision)[color],
               '  ': '  ',
           })

           const cursorUp = '\u001b[1A'
           const tableHeight = depth * 2 + 4 // bids + asks + headers

           log (' ') // empty line

           while (true) {

               const orderbook = await exchange.fetchOrderBook (symbol)

               log (symbol.green, exchange.iso8601 (exchange.milliseconds ()))

               log (asTable.configure ({ delimiter: ' | '.dim, right: true }) ([
                   ... orderbook.asks.slice (0, depth).reverse ().map (priceVolumeHelper ('red')),
                   // { price: '--------'.dim, amount: '--------'.dim },
                   ... orderbook.bids.slice (0, depth).map (priceVolumeHelper ('green')),
               ]))

               log (cursorUp.repeat (tableHeight))
           }

       } else {

           log.error ('Symbol', symbol.bright, 'not found')
       }


   } else {

       log ('Exchange ' + id.red + ' not found')
       printSupportedExchanges ()
   }
}

;(async function main () {

   if (process.argv.length > 4) {

       const id = process.argv[2]
       const symbol = process.argv[3].toUpperCase ()
       const depth = parseInt (process.argv[4])
       await printOrderBook (id, symbol, depth)

   } else {

       printUsage ()
   }

   process.exit ()

}) ()