How do you format a number to currency when using React native Expo?

How do I take a number like 10000 and have it output as $10,000.00? I even had a problem with String.format(...) with a Not a function error.

I followed numerous articles, all incomplete and none working. I don't need full internationalization, just the ability to format a number

You can use toFixed method for showing 2 decimal point.

let num = 1000; 
console.log(num.toFixed(2)); // 1000.00

And you can use Regex like this

function currencyFormat(num) {
   return '$' + num.toFixed(2).replace(/(\d)(?=(\d{3})+(?!\d))/g, '$1,')
}
console.log(currencyFormat(2665)); // $2,665.00

You can use this library react-number-format. It has these features

1. Prefix, suffix and thousand separator.
2. Custom format pattern.
3. Masking.
4. Custom formatting handler.
5. Format number in an input or format as a simple text

Sample usage

<NumberFormat value={2456981} displayType={'text'} thousandSeparator={true} prefix={'$'} />

Output : $2,456,981

Edit: Sorry -this is a React.js solution - not React Native. None of the above worked for me ... but this chap had the right idea / solution https://medium.com/@nidhinkumar/react-js-number-format-and-styling-a1a6e211e629

const numberFormat = (value) =>
  new Intl.NumberFormat('en-IN', {
    style: 'currency',
    currency: 'INR'
  }).format(value);

numberFormat(50000); //output as ₹ 50,000.00
numberFormat(10000); //output as ₹ 10,000.00

To avoid using libraries, you can use the following code

const defaultOptions = {
  significantDigits: 2,
  thousandsSeparator: ',',
  decimalSeparator: '.',
  symbol: '$'
}

const currencyFormatter = (value, options) => {
  if (typeof value !== 'number') value = 0.0
  options = { ...defaultOptions, ...options }
  value = value.toFixed(options.significantDigits)

  const [currency, decimal] = value.split('.')
  return `${options.symbol} ${currency.replace(
    /\B(?=(\d{3})+(?!\d))/g,
    options.thousandsSeparator
  )}${options.decimalSeparator}${decimal}`
}