[Number Formatter] src: https://developers.shopware.com/blog/2017/02/06/currency-formatting-is-easy-isnt-it/

NumberFormatter.js

function NumberFormatter(locale, opts) {
    var formatNumber,
        defaults = {
            style: 'currency',
            currency: 'EUR'
        };
    opts = opts || {};
    opts = Object.assign({}, defaults, opts);
    
    formatNumber = new Intl.NumberFormat(locale, opts);
    return formatNumber.format;
};

var formatter = new NumberFormatter('de-DE');
console.log(formatter(12.49));