Intl.NumberFormat either 0 or two fraction digits

Question

My formatter looks like this

const formatter = new Intl.NumberFormat('en-NZ', {    style: 'currency',    currency: 'NZD',    minimumFractionDigits: 2,  });

How can I adjust this so that whole numbers have 0 fraction digits

formatter.format(4); // want output "$4" 

whilst fractions always show two digits?

formatter.format(4.1); // want output "$4.10" 

Answer 1

The correct way to do it when using Intl.NumberFormat is to set both maximumFractionDigits and minimumFractionDigits options in constructor while validating input value using a modulo % for a whole number (per https://stackoverflow.com/a/49724586/1362535 which is a CORRECT answer!). The accepted answer is sort of string manipulation.

const fraction = new Intl.NumberFormat('en-NZ', {   style: 'currency',   currency: 'NZD',   minimumFractionDigits: 0,   maximumFractionDigits: 0, });  const formatter = new Intl.NumberFormat('en-NZ', {   style: 'currency',   currency: 'NZD',   minimumFractionDigits: 2, });  let number = 4.1;   if(number % 1 == 0) console.log(fraction.format(number));   else console.log(formatter.format(number));  number = 4;   if(number % 1 == 0) console.log(fraction.format(number));   else console.log(formatter.format(number));

Answer 2

You could try something like this:

formatter.format(amount).replace(/\D00$/, ''); 

Update:

In response to the many-months-later comment by @Marek, the above regex already handles differing decimal symbols (either . or ,), but it's true that it doesn't handle trailing currency symbols. That can be fixed this way:

formatter.format(amount).replace(/\D00(?=\D*$)/, '');