new Intl.NumberFormat('en-US', {

    style: 'decimal',

    useGrouping: true,

    minimumFractionDigits: 0,

    maximumFractionDigits: 3,

  }).format('100000.234')

const value = '100000.234';

​

function decimalFormat(value) {

​

  // fix for rounding issues, see Mozilla docs on method toFixed()

  const normalizedValue = value * 10 ** 3;

  const formattedValue = normalizedValue.toFixed(0);

  return +formattedValue / 10 ** 3;

}

​

function formatThousandsSeparator(value) {

  // TODO: consider replacing this later with  Intl.NumberFormat

  const parts = value.toString().split('.');

  parts[0] = parts[0].replace(/\B(?=(\d{3})+(?!\d))/g, ',');

  return parts.join('.');

}

​

decimalFormat(formatThousandsSeparator(value))