JavaScript - How do I convert unicode characters? English numbers to Persian numbers

Question

I'm building a software that takes integers from users and does some calculations and then outputs the result. The thing is that I want to take users numbers using English numbers(0, 1, 2, etc.) and I want to present the numbers using Persian numbers(like Arabic) in the output. I've read some topics on Unicode conversion and things like replace() and charCodeAt() but I can't understand the code.

Here's a piece of code.(It converts Persian numbers into English numbers but I want to do the opposite.)

 var yas ="٠١٢٣٤٥٦٧٨٩";
 yas = Number(yas.replace(/[٠١٢٣٤٥٦٧٨٩]/g, function (d) {
     return d.charCodeAt(0) - 1632;                
     }).replace(/[۰۱۲۳۴۵۶۷۸۹]/g, function (d) { return d.charCodeAt(0) - 1776; })
 );

Answer 1

That Persian-to-English script seems unnecessarily complicated, which makes me wonder if I'm missing something.

Basically, with such a limited data set, the simplest thing is to give yourself a map either way:

// The "Persian" here aren't just Persian, nor are the English just English.
// Both numeral sets are used in multiple languages...

// One time setup
var persian ="٠١٢٣٤٥٦٧٨٩";
var mapPtoE = Object.create(null);
var mapEtoP = Object.create(null);
persian.split("").forEach(function(glyph, index) {
  mapPtoE[glyph] = index;
  mapEtoP[index] = glyph;
});
// Convert one char "Persion" => "English"
function charPtoE(ch) {
  return mapPtoE[ch] || ch;
}
// Convert one char "English" => "Persion"
function charEtoP(ch) {
  return mapEtoP[ch] || ch;
}
// Convert the "Persian" digits in a string to "English"
function strPToE(s) {
  return s.replace(/[٠١٢٣٤٥٦٧٨٩]/g, charPtoE);
}
// Convert the "English" digits in a string to "Persian"
function strEToP(s) {
  return s.replace(/\d/g, charEtoP);
}

// Demonstrate converting "Persian" to "English"
console.log("Test A ٠١٢٣", "=>", strPToE("Test A ٠١٢٣"));
console.log("Test B ٦٥٤", "=>",  strPToE("Test B ٦٥٤"));
console.log("Test C ٧٨٩", "=>",  strPToE("Test C ٧٨٩"));

// Demonstrate converting "English" to "Persian"
console.log("Test A 0123", "=>", strEToP("Test A 0123"));
console.log("Test B 654", "=>",  strEToP("Test B 654"));
console.log("Test C 789", "=>",  strEToP("Test C 789"));

From your question it looks like there can be more than one form for 4 and 6 (pardon my ignorance); if so, you'll want to adjust the above to handle that in the "Persian" to "English" conversion, and pick one to use going the other way.