JSFiddle - React, Tailwind, and code Playground

JavaScript

var phoneNumber = "+62895326637865".replace("+62", "0");
var arr = phoneNumber.split("");
var subs = phoneNumber.substring(0,phoneNumber.length - 4);
var arrsubs = subs.split("");
var x = "";
var last4 =phoneNumber.substr(phoneNumber.length - 4);

arrsubs.forEach(e=>{
	return x+="x";
})

console.log(x + last4);
console.log(arr);
console.log(length);
console.log(subs);