[Proposal] Intl.NumberFormat is incomplete and needs a respective Parser

Tags: #<Tag:0x00007faafa39cdb0>


The internationalization API is a very simple way to convert numbers to a string format including comma/period placement and even currencies around the world. However, there is no way to reverse that API. This renders the Intl.numberFormat function fairly unusable, especially when converting back and forth between an integer, server format and a string, display format for input fields.

This can be solved using a number parser that involves the i18n info, such as locale and/or currency code. We could use the format patterns already associated with the locales, currencies, etc. to match floats in the given number string.

As this is my first post, I am looking for feedback on:

  • How do I obtain the number formats baked into the spec?
  • What additional information / investigations do I need to provide to make this proposal?


I wrote up a generic example, but I don’t think this will work for all locales:

 * @param {Array} locale Would be used to find the regex associated with the locale to be filtered out of the price 
 * @param {String} price
 * @returns {Number}
function NumberParse(locale, price) {
  let reSym = /\d|\.|\,|\-/gi;
  let numArray = price.match(reSym);
  let initSweep numArray.join('')
  initSweep = initSweep.replace(/\,/g, '.')
  if (initSweep[0] === '-') {
    initSweep = initSweep.replace(/\-/g, '')
    initSweep = '-'.concat(initSweep)
  else {
    initSweep = initSweep.replace(/\-/g, '')
  numArray = initSweep.split('.')
  let tempDec = '00'
  if (numArray.length > 1) {
    tempDec = numArray.pop();
  initSweep = numArray.join('')
  initSweep = initSweep.concat('.', tempDec)
  return parseFloat(initSweep)


The above code doesn’t work for currencies without decimal denominations, but I hope you understand it’s for demonstration purposes only and this could be resolved if I could use the locale information :wink:.


This handles negatives as well. If someone puts “-69.900,00 US-Dollar” it’ll be “-69900.00” after the initial sweep.


Anyone have suggestions on how to format the proposal?


What are the next steps for the proposal? @domenic