castlemaine - nodejs tool to convert foreign exchange currencies

castlemaine-conf.js

module.exports = {
  apiKey : 'YOUR OPEN EXCHANGE RATES API KEY'
  , sourceCcy : 'USD'
  , targetCcy : 'GBP'
}

castlemaine.js

#!/usr/bin/env node
// castlemaine - nodejs tool to convert foreign exchange currencies
// requires npm modules open-exchange-rates and money
// largely inspired by the demo code provided by the open-exchange-rates module


/*jshint laxcomma : true */
var oxr   = require('open-exchange-rates')
    ,fx   = require('money')
    ,conf = require('./castlemaine-conf');

oxr.set({ app_id: conf.apiKey });

oxr.latest(function() {
  // Apply exchange rates and base rate to `fx` library object:
  fx.rates = oxr.rates; fx.base = oxr.base;

  var amount, sourceCcy, targetCcy;

  if (process.argv.length < 3 || process.argv.length > 5) {
    usage();
    process.exit(1);
  }

  amount = process.argv[2];

  if (process.argv.length === 3) {
    sourceCcy = conf.sourceCcy;
    targetCcy = conf.targetCcy;
  }

 if (process.argv.length === 4) {
    sourceCcy = conf.sourceCcy;
    targetCcy = process.argv[3].toUpperCase();
  }

  if (process.argv.length === 5) {
    sourceCcy = process.argv[3].toUpperCase();
    targetCcy = process.argv[4].toUpperCase();
  }

  
  console.log('%d %s = %d %s', amount, sourceCcy, fx(amount).from(sourceCcy).to(targetCcy), targetCcy);
});

function usage() {
  var appName = process.argv[1].split('/')[7];
  console.log("error! insufficient arguments supplied!");
  console.log("examples");
  console.log('convert 12.50 %s to %s  - %s 12.5', conf.sourceCcy, conf.targetCcy, appName); 
  console.log('convert 12.50 %s to AED  - %s 12.5 AED', conf.sourceCcy, appName); 
  console.log('convert 12.50 USD to EUR  - %s 12.5 USD EUR', appName); 
}