Assigning a unique filename if filename already exists.

uniqueFileName2.js

  var i = 1;
  var array = fileName.split('.');
  var encryptFileName = `${array[0]}.${array[1]}.tdf3.html`;
  while (fs.existsSync(`./encrypt-out/${encryptFileName}`)) {
    encryptFileName = `${array[0]} (${i}).${array[1]}.tdf3.html`;
    i++;
  }