JavaScript Number.toLocaleString() with 4 digits after separator

Is there a way to get number.toLocaleString() with 4 digits after the comma?

Example:

var number = 49.9712;
document.getElementById('id').innerText = number.toLocaleString();

Result: 49,9712

But now it always returns number with 2 digits after comma: 49,97

You may use second argument to provide some options. In your case, with default locale:

number.toLocaleString(undefined, { minimumFractionDigits: 4 })

I found that

var number = 49.9712;
number.toLocaleString( { minimumFractionDigits: 4 })

gave the result of "49.971"

In order to actually get the 4 decimal place digits, I did this:

number.toLocaleString(undefined, { minimumFractionDigits: 4 })

Also filling in a country code worked:

number.toLocaleString('en-US', { minimumFractionDigits: 4 })

In both cases I got 49.9712 for the answer.

Quick solution:

call it like this:

console.log(localeN(value, 4));

function localeN(v, n) {
    var i, f;
  
    i = Math.floor(v);
    f = v - i;
    return i.toLocaleString() + f.toFixed(n).substr(1);
}

You cannot do this with toLocaleString() alone. But you can round to 4 decimal places before displaying:

var n = Math.round(number * 10000) / 10000;
document.getElementById('id').innerText = n.toLocaleString();