Using Vietnamese numerology, is your number lucky?

vietnameseLucky.js

const myArgs = process.argv.slice(2);

let computedNum = 99999;
let numString = myArgs[0];

while(computedNum > 9) {
  let sum = 0;
  for (var i = 0; i < numString.length; i++) {
    sum += parseInt(numString.charAt(i));
  }
  computedNum = sum;
  numString = computedNum + '';
}

switch(computedNum) {
  case 0:
  case 1:
  case 2:
  case 3:
    console.log('Not lucky. Not unlucky.');
    break;
  case 4:
    console.log('OMG you are screwed. Run away. Run far away.');
    break;
  case 5:
    console.log('Not lucky. Not unlucky.');
    break;
  case 6:
    console.log('I get a different answer every time I ask my wife if this is lucky.');
    break;
  case 7:
    console.log('Not lucky. Not unlucky.');
    break;
  case 8:
    console.log('This is a really lucky number.');
    break;
  case 9:
    console.log('This is the luckiest most lucky super awesome number ever.');
    break;
}

$ node vietnameseLucky.js 293921
This is a really lucky number.
$ node vietnameseLucky.js 607   
OMG you are screwed. Run away. Run far away.
$ node vietnameseLucky.js 202
OMG you are screwed. Run away. Run far away.
$ node vietnameseLucky.js 405
This is the luckiest most lucky super awesome number ever.