Transform numbers to words in lakh / crore system

Question

I'm writing some code that converts a given number into words, here's what I have got after googling. But I think it's a bit too long for such a simple task. Two Regular Expressions and two for loops, I want something simpler.

I am trying to achieve this in as few lines of code as possible. here's what I've come up with so far:

Any suggestions?

var th = ['','thousand','million', 'billion','trillion']; var dg = ['zero','one','two','three','four', 'five','six','seven','eight','nine'];  var tn = ['ten','eleven','twelve','thirteen', 'fourteen','fifteen','sixteen', 'seventeen','eighteen','nineteen'];  var tw = ['twenty','thirty','forty','fifty', 'sixty','seventy','eighty','ninety'];   function toWords(s) {     s = s.toString();     s = s.replace(/[\, ]/g,'');     if (s != parseFloat(s)) return 'not a number';     var x = s.indexOf('.');     if (x == -1)         x = s.length;     if (x > 15)         return 'too big';     var n = s.split('');      var str = '';     var sk = 0;     for (var i=0;   i < x;  i++) {         if ((x-i)%3==2) {              if (n[i] == '1') {                 str += tn[Number(n[i+1])] + ' ';                 i++;                 sk=1;             } else if (n[i]!=0) {                 str += tw[n[i]-2] + ' ';                 sk=1;             }         } else if (n[i]!=0) { // 0235             str += dg[n[i]] +' ';             if ((x-i)%3==0) str += 'hundred ';             sk=1;         }         if ((x-i)%3==1) {             if (sk)                 str += th[(x-i-1)/3] + ' ';             sk=0;         }     }          if (x != s.length) {         var y = s.length;         str += 'point ';         for (var i=x+1; i<y; i++)             str += dg[n[i]] +' ';     }     return str.replace(/\s+/g,' '); } 

Also, the above code converts to the English numbering system like Million/Billion, I need the South Asian numbering system, like in Lakhs and Crores.

Answer 1

Update: Looks like this is more useful than I thought. I've just published this on npm. https://www.npmjs.com/package/num-words

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Here's a shorter code. with one RegEx and no loops. converts as you wanted, in south asian numbering system

var a = ['','one ','two ','three ','four ', 'five ','six ','seven ','eight ','nine ','ten ','eleven ','twelve ','thirteen ','fourteen ','fifteen ','sixteen ','seventeen ','eighteen ','nineteen '];  var b = ['', '', 'twenty','thirty','forty','fifty', 'sixty','seventy','eighty','ninety'];    function inWords (num) {      if ((num = num.toString()).length > 9) return 'overflow';      n = ('000000000' + num).substr(-9).match(/^(\d{2})(\d{2})(\d{2})(\d{1})(\d{2})$/);      if (!n) return; var str = '';      str += (n[1] != 0) ? (a[Number(n[1])] || b[n[1][0]] + ' ' + a[n[1][1]]) + 'crore ' : '';      str += (n[2] != 0) ? (a[Number(n[2])] || b[n[2][0]] + ' ' + a[n[2][1]]) + 'lakh ' : '';      str += (n[3] != 0) ? (a[Number(n[3])] || b[n[3][0]] + ' ' + a[n[3][1]]) + 'thousand ' : '';      str += (n[4] != 0) ? (a[Number(n[4])] || b[n[4][0]] + ' ' + a[n[4][1]]) + 'hundred ' : '';      str += (n[5] != 0) ? ((str != '') ? 'and ' : '') + (a[Number(n[5])] || b[n[5][0]] + ' ' + a[n[5][1]]) + 'only ' : '';      return str;  }    document.getElementById('number').onkeyup = function () {      document.getElementById('words').innerHTML = inWords(document.getElementById('number').value);  };

<span id="words"></span>  <input id="number" type="text" />

The only limitation is, you can convert maximum of 9 digits, which I think is more than sufficient in most cases..