index.js

import React from 'react';
import { BigNumber } from 'bignumber.js';
import { Text } from 'react-native';

const reg2 = /-?([0-9,]+\.(([0]{0,2})[1-9]{1,2})?)|-?(0\.([0]+)?[1-9]{1,2})/g;

const FormattedNumber = ({
  val,
  children,
  type,
  style,
  trim,
  tokenType,
  language = 'en',
  testID,
}) => {
  const Element = type || Text;
  const bigNum = new BigNumber(val || children);
  const formatedNumber = bigNum.toFormat();
  const matched = formatedNumber.match(reg2);
  const normalizedVal =
    trim && matched && matched[0] !== '0.' && matched[0] !== '-0.'
      ? matched[0].replace(/\.$/, '')
      : formatedNumber;
  const valueWithoutSeparators = normalizedVal.replace(/,/g, '');
  const localizedVal = Number(valueWithoutSeparators).toLocaleString(
    `${language}-${language.toUpperCase()}`,
    { maximumFractionDigits: 20 }
  );
  return (
    <Element style={style} testID={testID}>
      {localizedVal} {tokenType || 'LSK'}
    </Element>
  );
};

export default FormattedNumber;