var money = 123456.12;
// display with correct formatting
money.toLocaleString('de-DE'); // "123.456,12"
// for currency, bad as we're leaving the precision to the gods of floating point numbers
money.toLocaleString('en-GB', { style: 'currency', currency: 'GBP' }); // "£123,456.12"
// for currency, good as we're using strings...
new Intl.NumberFormat('de-DE', { style: 'currency', currency: 'EUR' }).format('12312.12')