How to convert Persian and Arabic numbers inside a string to English using JavaScript?

Question

How can I convert Persian/Arabic numbers to English numbers with a simple function?

arabicNumbers = [\"١\", \"٢\", \"٣\", \"٤\", \"٥\", \"٦\", \"٧\", \"٨\",          


        

Answer 1

Oneliner of all 6 possible translations between English, Arabic, and persian Digits.

const e2p = s => s.replace(/\d/g, d => '۰۱۲۳۴۵۶۷۸۹'[d])
const e2a = s => s.replace(/\d/g, d => '٠١٢٣٤٥٦٧٨٩'[d])

const p2e = s => s.replace(/[۰-۹]/g, d => '۰۱۲۳۴۵۶۷۸۹'.indexOf(d))
const a2e = s => s.replace(/[٠-٩]/g, d => '٠١٢٣٤٥٦٧٨٩'.indexOf(d))

const p2a = s => s.replace(/[۰-۹]/g, d => '٠١٢٣٤٥٦٧٨٩'['۰۱۲۳۴۵۶۷۸۹'.indexOf(d)])
const a2p = s => s.replace(/[٠-٩]/g, d => '۰۱۲۳۴۵۶۷۸۹'['٠١٢٣٤٥٦٧٨٩'.indexOf(d)])

e2p("asdf1234") // asdf۱۲۳۴
e2a("asdf1234") // asdf١٢٣٤
p2e("asdf۱۲۳۴") // asdf1234
a2e("asdf١٢٣٤") // asdf1234
p2a("asdf۱۲۳۴") // asdf١٢٣٤
a2p("asdf١٢٣٤") // asdf۱۲۳۴

Explaination:

• (s => f(s))(x) is a lambda function that is immediately executed, and will be equal to f(x)
• s.replace(pattern, function) looks for matches of pattern in s, for every match m it will replace m with function(m) in the string.
• /\d/g is a regex pattern, \d means a digit in the English language, g means global. If you don't specify the g it will only match the first occurrence, otherwise it will match all the occurrences.
• In this case for every English digit d in the string, that digit will be replaced by '۰۱۲۳۴۵۶۷۸۹'[d] so, 3 will be replaced by the third index in that list('۰۱۲۳۴۵۶۷۸۹') which is '۳'
• /[۰-۹]/g is the equivalent regex for Persian digits this time we can't use the same method, before we took advantage of the fact that javascript is dynamically typed and that d is automatically converted from a string(regex match) to a number(array index) (you can do '1234'['1'] in javascript which is the same as '1234'[1])
• but this time we can't do that because '1234'['۱'] is invalid. so we use a trick here and use indexOf which is a function that tells us the index of an element in an array(here a character in a string) so, '۰۱۲۳۴۵۶۷۸۹'.indexOf(۳) will give us 3 because '۳' is the third index in the string '۰۱۲۳۴۵۶۷۸۹'

Answer 2

this is a simple way to do that:

function toEnglishDigits(str) {

    // convert persian digits [۰۱۲۳۴۵۶۷۸۹]
    var e = '۰'.charCodeAt(0);
    str = str.replace(/[۰-۹]/g, function(t) {
        return t.charCodeAt(0) - e;
    });

    // convert arabic indic digits [٠١٢٣٤٥٦٧٨٩]
    e = '٠'.charCodeAt(0);
    str = str.replace(/[٠-٩]/g, function(t) {
        return t.charCodeAt(0) - e;
    });
    return str;
}

an example:

console.log(toEnglishDigits("abc[0123456789][٠١٢٣٤٥٦٧٨٩][۰۱۲۳۴۵۶۷۸۹]"));
// expected result => abc[0123456789][0123456789][0123456789]

Answer 3

Transforms any Persian or Arabic (or mixed) number to "English" numbers (Hindu–Arabic numerals)

var transformNumbers = (function(){
    var numerals = {
        persian : ["۰", "۱", "۲", "۳", "۴", "۵", "۶", "۷", "۸", "۹"],
        arabic  : ["٠", "١", "٢", "٣", "٤", "٥", "٦", "٧", "٨", "٩"]
    };

    function fromEnglish(str, lang){
        var i, len = str.length, result = "";

        for( i = 0; i < len; i++ )
            result += numerals[lang][str[i]]; 

        return result;
    }

    return {
        toNormal : function(str){
            var num, i, len = str.length, result = "";

            for( i = 0; i < len; i++ ){
                num = numerals["persian"].indexOf(str[i]);
                num = num != -1 ? num : numerals["arabic"].indexOf(str[i]);
                if( num == -1 ) num = str[i];
                result += num; 
            }
              
            return result;
        },

        toPersian : function(str, lang){
            return fromEnglish(str, "persian");
        },

        toArabic : function(str){
            return fromEnglish(str, "arabic");
        }
    }
})();

//////// ON INPUT EVENT //////////////

document.querySelectorAll('input')[0].addEventListener('input', onInput_Normal);
document.querySelectorAll('input')[1].addEventListener('input', onInput_Arabic);

function onInput_Arabic(){
   var _n = transformNumbers.toArabic(this.value);
   console.clear();
   console.log( _n )
}

function onInput_Normal(){
   var _n = transformNumbers.toNormal(this.value);
   console.clear();
   console.log( _n )
}

input{ width:90%; margin-bottom:1em; font-size:1.5em; padding:5px; }

<input placeholder="write in Arabic numerals">

<input placeholder="write in normal numerals">