Convert digits into words with JavaScript

Question

I am making a code which converts the given amount into words, heres is what I have got after googling. But I think its a little lengthy code to achieve a simple task. Two R

Answer 1

You might want to try it recursive. It works for numbers between 0 and 999999. Keep in mind that (~~) does the same as Math.floor

var num = "zero one two three four five six seven eight nine ten eleven twelve thirteen fourteen fifteen sixteen seventeen eighteen nineteen".split(" ");
var tens = "twenty thirty forty fifty sixty seventy eighty ninety".split(" ");

function number2words(n){
    if (n < 20) return num[n];
    var digit = n%10;
    if (n < 100) return tens[~~(n/10)-2] + (digit? "-" + num[digit]: "");
    if (n < 1000) return num[~~(n/100)] +" hundred" + (n%100 == 0? "": " " + number2words(n%100));
    return number2words(~~(n/1000)) + " thousand" + (n%1000 != 0? " " + number2words(n%1000): "");
}

Answer 2

var inWords = function(totalRent){
//console.log(totalRent);
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'];
var number = parseFloat(totalRent).toFixed(2).split(".");
var num = parseInt(number[0]);
var digit = parseInt(number[1]);
//console.log(num);
if ((num.toString()).length > 9)  return 'overflow';
var n = ('000000000' + num).substr(-9).match(/^(\d{2})(\d{2})(\d{2})(\d{1})(\d{2})$/);
var d = ('00' + digit).substr(-2).match(/^(\d{2})$/);;
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) ? (a[Number(n[5])] || b[n[5][0]] + ' ' + a[n[5][1]]) + 'Rupee ' : '';
str += (d[1] != 0) ? ((str != '' ) ? "and " : '') + (a[Number(d[1])] || b[d[1][0]] + ' ' + a[d[1][1]]) + 'Paise ' : 'Only!';
console.log(str);
return str;
}

This is modified code supports for Indian Rupee with 2 decimal place.

Answer 3

I spent a while developing a better solution to this. It can handle very big numbers but once they get over 16 digits you have pass the number in as a string. Something about the limit of JavaScript numbers.

    function numberToEnglish( n ) {
        
        var string = n.toString(), units, tens, scales, start, end, chunks, chunksLen, chunk, ints, i, word, words, and = 'and';

        /* Remove spaces and commas */
        string = string.replace(/[, ]/g,"");

        /* Is number zero? */
        if( parseInt( string ) === 0 ) {
            return 'zero';
        }
        
        /* Array of units as words */
        units = [ '', 'one', 'two', 'three', 'four', 'five', 'six', 'seven', 'eight', 'nine', 'ten', 'eleven', 'twelve', 'thirteen', 'fourteen', 'fifteen', 'sixteen', 'seventeen', 'eighteen', 'nineteen' ];
        
        /* Array of tens as words */
        tens = [ '', '', 'twenty', 'thirty', 'forty', 'fifty', 'sixty', 'seventy', 'eighty', 'ninety' ];
        
        /* Array of scales as words */
        scales = [ '', 'thousand', 'million', 'billion', 'trillion', 'quadrillion', 'quintillion', 'sextillion', 'septillion', 'octillion', 'nonillion', 'decillion', 'undecillion', 'duodecillion', 'tredecillion', 'quatttuor-decillion', 'quindecillion', 'sexdecillion', 'septen-decillion', 'octodecillion', 'novemdecillion', 'vigintillion', 'centillion' ];
        
        /* Split user argument into 3 digit chunks from right to left */
        start = string.length;
        chunks = [];
        while( start > 0 ) {
            end = start;
            chunks.push( string.slice( ( start = Math.max( 0, start - 3 ) ), end ) );
        }
        
        /* Check if function has enough scale words to be able to stringify the user argument */
        chunksLen = chunks.length;
        if( chunksLen > scales.length ) {
            return '';
        }
        
        /* Stringify each integer in each chunk */
        words = [];
        for( i = 0; i < chunksLen; i++ ) {
            
            chunk = parseInt( chunks[i] );
            
            if( chunk ) {
                
                /* Split chunk into array of individual integers */
                ints = chunks[i].split( '' ).reverse().map( parseFloat );
            
                /* If tens integer is 1, i.e. 10, then add 10 to units integer */
                if( ints[1] === 1 ) {
                    ints[0] += 10;
                }
                
                /* Add scale word if chunk is not zero and array item exists */
                if( ( word = scales[i] ) ) {
                    words.push( word );
                }
                
                /* Add unit word if array item exists */
                if( ( word = units[ ints[0] ] ) ) {
                    words.push( word );
                }
                
                /* Add tens word if array item exists */
                if( ( word = tens[ ints[1] ] ) ) {
                    words.push( word );
                }
                
                /* Add 'and' string after units or tens integer if: */
                if( ints[0] || ints[1] ) {
                    
                    /* Chunk has a hundreds integer or chunk is the first of multiple chunks */
                    if( ints[2] || ! i && chunksLen ) {
                        words.push( and );
                    }
                
                }
                
                /* Add hundreds word if array item exists */
                if( ( word = units[ ints[2] ] ) ) {
                    words.push( word + ' hundred' );
                }
                
            }
            
        }
        
        return words.reverse().join( ' ' );
        
    }


// - - - - - Tests - - - - - -
function test(v) {
  var sep = ('string'==typeof v)?'"':'';
  console.log("numberToEnglish("+sep + v.toString() + sep+") = "+numberToEnglish(v));
}
test(2);
test(721);
test(13463);
test(1000001);
test("21,683,200,000,621,384");

Answer 4

"Deceptively simple task." – Potatoswatter

Indeed. There's many little devils hanging out in the details of this problem. It was very fun to solve tho.

EDIT: This update takes a much more compositional approach. Previously there was one big function which wrapped a couple other proprietary functions. Instead, this time we define generic reusable functions which could be used for many varieties of tasks. More about those after we take a look at numToWords itself …

// numToWords :: (Number a, String a) => a -> String
let numToWords = n => {
  let a = [
    '', 'one', 'two', 'three', 'four',
    'five', 'six', 'seven', 'eight', 'nine',
    'ten', 'eleven', 'twelve', 'thirteen', 'fourteen',
    'fifteen', 'sixteen', 'seventeen', 'eighteen', 'nineteen'
  ];
  let b = [
    '', '', 'twenty', 'thirty', 'forty',
    'fifty', 'sixty', 'seventy', 'eighty', 'ninety'
  ];
  let g = [
    '', 'thousand', 'million', 'billion', 'trillion', 'quadrillion',
    'quintillion', 'sextillion', 'septillion', 'octillion', 'nonillion'
  ];
  // this part is really nasty still
  // it might edit this again later to show how Monoids could fix this up
  let makeGroup = ([ones,tens,huns]) => {
    return [
      num(huns) === 0 ? '' : a[huns] + ' hundred ',
      num(ones) === 0 ? b[tens] : b[tens] && b[tens] + '-' || '',
      a[tens+ones] || a[ones]
    ].join('');
  };
  // "thousands" constructor; no real good names for this, i guess
  let thousand = (group,i) => group === '' ? group : `${group} ${g[i]}`;
  // execute !
  if (typeof n === 'number') return numToWords(String(n));
  if (n === '0')             return 'zero';
  return comp (chunk(3)) (reverse) (arr(n))
    .map(makeGroup)
    .map(thousand)
    .filter(comp(not)(isEmpty))
    .reverse()
    .join(' ');
};

Here are the dependencies:

You'll notice these require next to no documentation because their intents are immediately clear. chunk might be the only one that takes a moment to digest, but it's really not too bad. Plus the function name gives us a pretty good indication what it does, and it's probably a function we've encountered before.

const arr = x => Array.from(x);
const num = x => Number(x) || 0;
const str = x => String(x);
const isEmpty = xs => xs.length === 0;
const take = n => xs => xs.slice(0,n);
const drop = n => xs => xs.slice(n);
const reverse = xs => xs.slice(0).reverse();
const comp = f => g => x => f (g (x));
const not = x => !x;
const chunk = n => xs =>
  isEmpty(xs) ? [] : [take(n)(xs), ...chunk (n) (drop (n) (xs))];

"So these make it better?"

Look at how the code has cleaned up significantly

// NEW CODE (truncated)
return comp (chunk(3)) (reverse) (arr(n))
    .map(makeGroup)
    .map(thousand)
    .filter(comp(not)(isEmpty))
    .reverse()
    .join(' ');

// OLD CODE (truncated)
let grp = n => ('000' + n).substr(-3);
let rem = n => n.substr(0, n.length - 3);
let cons = xs => x => g => x ? [x, g && ' ' + g || '', ' ', xs].join('') : xs;
let iter = str => i => x => r => {
  if (x === '000' && r.length === 0) return str;
  return iter(cons(str)(fmt(x))(g[i]))
             (i+1)
             (grp(r))
             (rem(r));
};
return iter('')(0)(grp(String(n)))(rem(String(n)));

Most importantly, the utility functions we added in the new code can be used other places in your app. This means that, as a side effect of implementing numToWords in this way, we get the other functions for free. Bonus soda !

Some tests

console.log(numToWords(11009));
//=> eleven thousand nine

console.log(numToWords(10000001));
//=> ten million one 

console.log(numToWords(987));
//=> nine hundred eighty-seven

console.log(numToWords(1015));
//=> one thousand fifteen

console.log(numToWords(55111222333));
//=> fifty-five billion one hundred eleven million two hundred 
//   twenty-two thousand three hundred thirty-three

console.log(numToWords("999999999999999999999991"));
//=> nine hundred ninety-nine sextillion nine hundred ninety-nine
//   quintillion nine hundred ninety-nine quadrillion nine hundred
//   ninety-nine trillion nine hundred ninety-nine billion nine
//   hundred ninety-nine million nine hundred ninety-nine thousand
//   nine hundred ninety-one

console.log(numToWords(6000753512));
//=> six billion seven hundred fifty-three thousand five hundred
//   twelve 

Runnable demo

const arr = x => Array.from(x);
const num = x => Number(x) || 0;
const str = x => String(x);
const isEmpty = xs => xs.length === 0;
const take = n => xs => xs.slice(0,n);
const drop = n => xs => xs.slice(n);
const reverse = xs => xs.slice(0).reverse();
const comp = f => g => x => f (g (x));
const not = x => !x;
const chunk = n => xs =>
  isEmpty(xs) ? [] : [take(n)(xs), ...chunk (n) (drop (n) (xs))];

// numToWords :: (Number a, String a) => a -> String
let numToWords = n => {
  
  let a = [
    '', 'one', 'two', 'three', 'four',
    'five', 'six', 'seven', 'eight', 'nine',
    'ten', 'eleven', 'twelve', 'thirteen', 'fourteen',
    'fifteen', 'sixteen', 'seventeen', 'eighteen', 'nineteen'
  ];
  
  let b = [
    '', '', 'twenty', 'thirty', 'forty',
    'fifty', 'sixty', 'seventy', 'eighty', 'ninety'
  ];
  
  let g = [
    '', 'thousand', 'million', 'billion', 'trillion', 'quadrillion',
    'quintillion', 'sextillion', 'septillion', 'octillion', 'nonillion'
  ];
  
  // this part is really nasty still
  // it might edit this again later to show how Monoids could fix this up
  let makeGroup = ([ones,tens,huns]) => {
    return [
      num(huns) === 0 ? '' : a[huns] + ' hundred ',
      num(ones) === 0 ? b[tens] : b[tens] && b[tens] + '-' || '',
      a[tens+ones] || a[ones]
    ].join('');
  };
  
  let thousand = (group,i) => group === '' ? group : `${group} ${g[i]}`;
  
  if (typeof n === 'number')
    return numToWords(String(n));
  else if (n === '0')
    return 'zero';
  else
    return comp (chunk(3)) (reverse) (arr(n))
      .map(makeGroup)
      .map(thousand)
      .filter(comp(not)(isEmpty))
      .reverse()
      .join(' ');
};


console.log(numToWords(11009));
//=> eleven thousand nine

console.log(numToWords(10000001));
//=> ten million one 

console.log(numToWords(987));
//=> nine hundred eighty-seven

console.log(numToWords(1015));
//=> one thousand fifteen

console.log(numToWords(55111222333));
//=> fifty-five billion one hundred eleven million two hundred 
//   twenty-two thousand three hundred thirty-three

console.log(numToWords("999999999999999999999991"));
//=> nine hundred ninety-nine sextillion nine hundred ninety-nine
//   quintillion nine hundred ninety-nine quadrillion nine hundred
//   ninety-nine trillion nine hundred ninety-nine billion nine
//   hundred ninety-nine million nine hundred ninety-nine thousand
//   nine hundred ninety-one

console.log(numToWords(6000753512));
//=> six billion seven hundred fifty-three thousand five hundred
//   twelve

---

You can transpile the code using babel.js if you want to see the ES5 variant

Answer 5

 <html>

<head>

    <title>HTML - Convert numbers to words using JavaScript</title>

    <script  type="text/javascript">
    	function onlyNumbers(evt) {
    var e = event || evt; // For trans-browser compatibility
    var charCode = e.which || e.keyCode;

    if (charCode > 31 && (charCode < 48 || charCode > 57))
        return false;
    return true;
}

function NumToWord(inputNumber, outputControl) {
    var str = new String(inputNumber)
    var splt = str.split("");
    var rev = splt.reverse();
    var once = ['Zero', ' One', ' Two', ' Three', ' Four', ' Five', ' Six', ' Seven', ' Eight', ' Nine'];
    var twos = ['Ten', ' Eleven', ' Twelve', ' Thirteen', ' Fourteen', ' Fifteen', ' Sixteen', ' Seventeen', ' Eighteen', ' Nineteen'];
    var tens = ['', 'Ten', ' Twenty', ' Thirty', ' Forty', ' Fifty', ' Sixty', ' Seventy', ' Eighty', ' Ninety'];

    numLength = rev.length;
    var word = new Array();
    var j = 0;

    for (i = 0; i < numLength; i++) {
        switch (i) {

            case 0:
                if ((rev[i] == 0) || (rev[i + 1] == 1)) {
                    word[j] = '';
                }
                else {
                    word[j] = '' + once[rev[i]];
                }
                word[j] = word[j];
                break;

            case 1:
                aboveTens();
                break;

            case 2:
                if (rev[i] == 0) {
                    word[j] = '';
                }
                else if ((rev[i - 1] == 0) || (rev[i - 2] == 0)) {
                    word[j] = once[rev[i]] + " Hundred ";
                }
                else {
                    word[j] = once[rev[i]] + " Hundred and";
                }
                break;

            case 3:
                if (rev[i] == 0 || rev[i + 1] == 1) {
                    word[j] = '';
                }
                else {
                    word[j] = once[rev[i]];
                }
                if ((rev[i + 1] != 0) || (rev[i] > 0)) {
                    word[j] = word[j] + " Thousand";
                }
                break;

                
            case 4:
                aboveTens();
                break;

            case 5:
                if ((rev[i] == 0) || (rev[i + 1] == 1)) {
                    word[j] = '';
                }
                else {
                    word[j] = once[rev[i]];
                }
                if (rev[i + 1] !== '0' || rev[i] > '0') {
                    word[j] = word[j] + " Lakh";
                }
                 
                break;

            case 6:
                aboveTens();
                break;

            case 7:
                if ((rev[i] == 0) || (rev[i + 1] == 1)) {
                    word[j] = '';
                }
                else {
                    word[j] = once[rev[i]];
                }
                if (rev[i + 1] !== '0' || rev[i] > '0') {
                    word[j] = word[j] + " Crore";
                }                
                break;

            case 8:
                aboveTens();
                break;

            //            This is optional. 

            //            case 9:
            //                if ((rev[i] == 0) || (rev[i + 1] == 1)) {
            //                    word[j] = '';
            //                }
            //                else {
            //                    word[j] = once[rev[i]];
            //                }
            //                if (rev[i + 1] !== '0' || rev[i] > '0') {
            //                    word[j] = word[j] + " Arab";
            //                }
            //                break;

            //            case 10:
            //                aboveTens();
            //                break;

            default: break;
        }
        j++;
    }

    function aboveTens() {
        if (rev[i] == 0) { word[j] = ''; }
        else if (rev[i] == 1) { word[j] = twos[rev[i - 1]]; }
        else { word[j] = tens[rev[i]]; }
    }

    word.reverse();
    var finalOutput = '';
    for (i = 0; i < numLength; i++) {
        finalOutput = finalOutput + word[i];
    }
    document.getElementById(outputControl).innerHTML = finalOutput;
}
    </script>

</head>

<body>

    <h1>

        HTML - Convert numbers to words using JavaScript</h1>

    <input id="Text1" type="text" onkeypress="return onlyNumbers(this.value);" onkeyup="NumToWord(this.value,'divDisplayWords');"

        maxlength="9" style="background-color: #efefef; border: 2px solid #CCCCC; font-size: large" />

    <br />

    <br />

    <div id="divDisplayWords" style="font-size: 13; color: Teal; font-family: Arial;">

    </div>

</body>

</html>

Answer 6

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

---

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..