convertir el número en palabras javascript lakh

function numDifferentiation(value) {
  var val = Math.abs(value)
  if (val >= 10000000) {
    val = (val / 10000000).toFixed(2) + ' Cr';
  } else if (val >= 100000) {
    val = (val / 100000).toFixed(2) + ' Lac';
  }
  return val;
}
console.log(numDifferentiation(-500000))
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