text: function addPrefix0x(hexString){
      return hexString.startsWith('0x') ? hexString : `0x${hexString}`
  }
  
  function removePrefix0x(hexString){
      return hexString.startsWith('0x') ? hexString.substring(2) : hexString
  }
  
  function compressHex(hex) {
    hex = removePrefix0x(hex);
    return new Buffer(hex, 'hex').toString('base64');
  }
  
  function decompressString(compressedString) {
    const hex = new Buffer(compressedString, 'base64').toString('hex');
    return addPrefix0x(hex);
  }
  
  module.exports = {
      addPrefix0x,
      removePrefix0x,
      compressHex,
      decompressString
  }