Number formatting, grouping digits according to the localization.

const usNumberFormat = new Intl.NumberFormat('en-US');
const esNumberFormat = new Intl.NumberFormat('es-ES');

const usNumber = usNumberFormat.format(99999999.99); // "99,999,999.99"
const esNumber = esNumberFormat.format(99999999.99); // "99.999.999,99"

Currency formatting, grouping digits and placing the currency symbol according to the localization.

const usCurrencyFormat = new Intl.NumberFormat('en-US', {style: 'currency', currency: 'USD'})
const esCurrencyFormat = new Intl.NumberFormat('es-ES', {style: 'currency', currency: 'EUR'})

const usCurrency = usCurrencyFormat.format(100.10); // "$100.10"
const esCurrency = esCurrencyFormat.format(100.10); // "100.10 €"

Date time formatting, according to the localization.

const usDateTimeFormatting = new Intl.DateTimeFormat('en-US');
const esDateTimeFormatting = new Intl.DateTimeFormat('es-ES');

const usDate = usDateTimeFormatting.format(new Date('2016-07-21')); // "7/21/2016"
const esDate = esDateTimeFormatting.format(new Date('2016-07-21')); // "21/7/2016"