JSFiddle - React, Tailwind, and code Playground

by Neeraj Yadav

JavaScript

//reformat telephone number.....
function ReFormat(str) {
  var str = str.replace(/ /g, '');
  str = str.replace(/-/g, ''); //str.replace(new RegExp('-','g'), '');

  var len = str.length;
  var insertAt = Math.floor(Math.sqrt(len));

  var arr = [];
  for (var i = 0, j = 0; i < len;) {
    var newLen = len - (insertAt * j);
    if (newLen - insertAt === 1) --insertAt;
    arr.push(str.substr(i, insertAt));
    i += insertAt;
    j++;
  }
  return arr.join("-");
}

alert(ReFormat("0 -  17985--324"));