localization - Is there a way to reverse the formatting by Intl.NumberFormat in JavaScript

Question

The Intl.NumberFormat (see Mozilla's doc) provides a nice way in Javascript to format numbers into a current locale`s version like this:

new Intl.NumberFormat().format(3400); // returns "3.400" for German locale

But I couldn't find a way to reverse this formatting. Is there something like

new Intl.NumberFormat().unformat("3.400"); // returns 3400 for German locale

Thanks for any help.

Answer 1

I have found a workaround:

/**
 * Parse a localized number to a float.
 * @param {string} stringNumber - the localized number
 * @param {string} locale - [optional] the locale that the number is represented in. Omit this parameter to use the current locale.
 */
function parseLocaleNumber(stringNumber, locale) {
    var thousandSeparator = Intl.NumberFormat(locale).format(11111).replace(/p{Number}/gu, '');
    var decimalSeparator = Intl.NumberFormat(locale).format(1.1).replace(/p{Number}/gu, '');

    return parseFloat(stringNumber
        .replace(new RegExp('\' + thousandSeparator, 'g'), '')
        .replace(new RegExp('\' + decimalSeparator), '.')
    );
}

Using it like this:

parseLocaleNumber('3.400,5', 'de');
parseLocaleNumber('3.400,5'); // or if you have German locale settings
// results in: 3400.5

Not the nicest solution but it works :-)

If anyone knows a better way of achieving this, feel free to post your answer.

Update

• Wrapped in a complete reusable function
• Using the regex class p{Number} to extract the separator. So that it also works with non-arabic digits.
• Using number with 5 places to support languages where numbers are separated at every fourth digit.