var date = new Date(Date.UTC(2012, 11, 20, 3, 0, 0));
// Results below assume UTC timezone - your results may vary

console.log(new Intl.DateTimeFormat('en-US').format(date));
// expected output: "12/20/2012"

console.log(new Intl.DateTimeFormat('en-GB').format(date));
// expected output: "20/12/2012"

// Include a fallback language, in this case Indonesian
console.log(new Intl.DateTimeFormat(['ban', 'id']).format(date));
// expected output: "20/12/2012"