app.js

const app = require('./lib/index'),
colors = require('colors/safe'),
{scanf} = require('nodejs-scanf');

console.log(colors.green('Please input value in format: from to money'));
console.log(colors.italic.red('Ex: USD EUR 100'));
console.log(colors.bold(':help  -> if you need help'));

// input currency change and value maney
var print = function (params, params1) {
    console.log(colors.blue(' %s')+colors.magenta(' is  %s'),params,params1);
}

scanf('%s %s %f', function(from, to,value) {
    
    if (from.toUpperCase()==':HELP') {
        app().help();
	}
	else{
        app().result(from,to,value,print);
	}
});
    

index.js

module.exports = function () {
    
    let API = require('currency-conversion');

    // api key for https://currencylayer.com/
    let api = new API({
	    access_key: ['1d36e5db73566dda4cf57cb2af474e19'],
    });

    // query for get live currency value
    var liveQuery = {
	source: 'USD',
	currencies: []
	};
	
    var currency = {
        help: function () {
			api.list(liveQuery, function (err, result) {
				if (err) {
					console.log(err);
					 console.log('Live (Error): ' + JSON.stringify(err));
				}else{	
					console.log();
					console.log('Currencies: ');			
					console.log(result.currencies);
				}
			});
        },
        conversion: function (value,rate) {
			return value*rate;
		},
		result: function (from, to, value,collback) {
			var _this = this;
			api.live(liveQuery, function (err, result) {
				if (err) {
					console.log(err);
					 console.log('Live (Error): ' + JSON.stringify(err));
				}else{	
					var string = JSON.stringify(result.quotes);
					var quotes = JSON.parse(string);
					 
					var _from = quotes['USD'+from], _to = quotes['USD'+to];
					 
					collback(value+' '+from,from == 'USD' ? _this.conversion(value,_to)+' '+to : _this.conversion(value,_to/_from)+ ' '+to);
				}
			});
		}
    };

    return currency;

};

package.json

{
  "name": "currencyconversion",
  "version": "1.0.0",
  "description": "App for currency conversion in the terminal",
  "main": "app.js",
  "bin": {
		"CurrencyConversion": "app.js"
	},
	"preferGlobal": "true",
  "scripts": {
    "test": "test.js"
  },
  "keywords": [
    "currency",
    "money",
    "conversão",
    "divisas"
  ],
  "author": "Jairo Duarte",
  "license": "MIT",
  "devDependencies": {
    "mocha": "^3.5.3",
    "mockery": "^2.1.0",
    "sinon": "^3.3.0"
  },
  "dependencies": {
    "nodejs-scanf": "1.1.0",
    "currency-conversion": "0.2.4",
    "colors": "^1.1.2"
  }
}