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

Lot of good answers. I needed mine for Indian (South Asian) numbering system. I modified one of the codes above - attaching it here, in case, someone else needs this. In the Indian numbering system, groups after thousands are in in 2 digits, not 3 as in the western system.

var IS_SOUTH_ASIAN = true;
function int_to_words(int) {
  if (int === 0) return 'zero';

  var ONES_WORD  = ['','one','two','three','four','five','six','seven','eight','nine','ten','eleven','twelve','thirteen','fourteen','fifteen','sixteen','seventeen','eighteen','nineteen'];
  var TENS_WORD  = ['','','twenty','thirty','fourty','fifty','sixty','seventy','eighty','ninety'];
  var SCALE_WORD_WESTERN = ['','thousand','million','billion','trillion','quadrillion','quintillion','sextillion','septillion','octillion','nonillion'];
  var SCALE_WORD_SOUTH_ASIAN = ['','thousand','lakh','crore','arab','kharab','neel','padma','shankh','***','***'];

  var GROUP_SIZE = (typeof IS_SOUTH_ASIAN != "undefined" && IS_SOUTH_ASIAN) ? 2 : 3;
  var SCALE_WORD = (typeof IS_SOUTH_ASIAN != "undefined" && IS_SOUTH_ASIAN) ? SCALE_WORD_SOUTH_ASIAN : SCALE_WORD_WESTERN;


  // Return string of first three digits, padded with zeros if needed
  function get_first_3(str) {
    return ('000' + str).substr(-(3));
  }
  function get_first(str) { //-- Return string of first GROUP_SIZE digits, padded with zeros if needed, if group size is 2, make it size 3 by prefixing with a '0'
    return (GROUP_SIZE == 2 ? '0' : '') + ('000' + str).substr(-(GROUP_SIZE));
  }


  // Return string of digits with first three digits chopped off
  function get_rest_3(str) {
    return str.substr(0, str.length - 3);
  }
  function get_rest(str) { // Return string of digits with first GROUP_SIZE digits chopped off
    return str.substr(0, str.length - GROUP_SIZE);
  }

  // Return string of triplet convereted to words
  function triplet_to_words(_3rd, _2nd, _1st) {
    return  (_3rd == '0' ? '' : ONES_WORD[_3rd] + ' hundred ') + 
            (_1st == '0' ? TENS_WORD[_2nd] : TENS_WORD[_2nd] && TENS_WORD[_2nd] + '-' || '') + 
            (ONES_WORD[_2nd + _1st] || ONES_WORD[_1st]);  //-- 1st one returns one-nineteen - second one returns one-nine
  }

  // Add to result, triplet words with scale word
  function add_to_result(result, triplet_words, scale_word) {
    return triplet_words ? triplet_words + (scale_word && ' ' + scale_word || '') + ' ' + result : result;
  }

  function recurse (result, scaleIdx, first, rest) {
    if (first == '000' && rest.length === 0) return result;
    var newResult = add_to_result (result, triplet_to_words (first[0], first[1], first[2]), SCALE_WORD[scaleIdx]);
    return recurse (newResult, ++scaleIdx, get_first(rest), get_rest(rest));
  }

  return recurse ('', 0, get_first_3(String(int)), get_rest_3(String(int)));
}

Answer 2

This is also in response to naomik's excellent post! Unfortunately I don't have the rep to post in the correct place but I leave this here in case it can help anyone.

If you need British English written form you need to make some adaptions to the code. British English differs from the American in a couple of ways. Basically you need to insert the word 'and' in two specific places.

1. After a hundred assuming there are tens and ones. E.g One hundred and ten. One thousand and seventeen. NOT One thousand one hundred and.
2. In certain edges, after a thousand, a million, a billion etc. when there are no smaller units. E.g. One thousand and ten. One million and forty four. NOT One million and one thousand.

The first situation can be addressed by checking for 10s and 1s in the makeGroup method and appending 'and' when they exist.

makeGroup = ([ones,tens,huns]) => {
var adjective = this.num(ones) ? ' hundred and ' : this.num(tens) ? ' hundred and ' : ' hundred';
return [
  this.num(huns) === 0 ? '' : this.a[huns] + adjective,
  this.num(ones) === 0 ? this.b[tens] : this.b[tens] && this.b[tens] + '-' || '',
  this.a[tens+ones] || this.a[ones]
].join('');

};

The second case is more complicated. It is equivalent to

• add 'and' to 'a million, a thousand', or 'a billion' if the antepenultimate number is zero. e.g.

1,100,057 one million one hundred thousand and fifty seven. 5,000,006 five million and six

I think this could be implemented in @naomik's code through the use of a filter function but I wasn't able to work out how. In the end I settled on hackily looping through the returned array of words and using indexOf to look for instances where the word 'hundred' was missing from the final element.

Answer 3

    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");