Convert Arabic/Persian numbers to English numbers in JavaScript

arabic-nums-to-english-nums.js

function conv2EnNum(str){
  return parseFloat(str
    .replace(/[٠١٢٣٤٥٦٧٨٩]/g, function (d) { return d.charCodeAt(0) - 1632; }) // Convert Arabic numbers
    .replace(/[۰۱۲۳۴۵۶۷۸۹]/g, function (d) { return d.charCodeAt(0) - 1776; }) // Convert Persian numbers
  )*1;
}

// Examples:
alert(conv2EnNum('٠١٢٣٤٥٦٧٨٩')); //  -> 01213456789
alert(conv2EnNum('١٣.٥'));       //  -> 13.5
alert(conv2EnNum('۴۷۶'));        //  -> 476

What is the role of *1 at the end of the function?
😂