How to use openpgp

const validateSignature = async (version, filename) => {
 console.log(`> validating signature for ${filename}`)

 const filepath = `${cachePath}/${version}/${filename}`

 const ctMessage = await fs.readFileAsync(`${filepath}`, 'utf8')
 const ctSignature = await fs.readFileAsync(`${filepath}.asc`, 'utf8')
 const ctPubKey = pubKey

 const options = {
  message: await openpgp.cleartext.readArmored(ctSignature),
  publicKeys: (await openpgp.key.readArmored(ctPubKey)).keys
 }

 const valid = await openpgp.verify(options)

 if (typeof valid.signatures === 'undefined' && typeof valid.signatures[0] === 'undefined') {
  throw new Error('Invalid Signature')
 }

 if (valid.signatures[0].valid === false) {
  throw new Error('PGP Signature is not valid')
 }
}

return Promise.resolve().then(()=>{
 let options = {
  message: openpgp.cleartext.readArmored(armoredText), // parse armored message
  publicKeys: openpgp.key.readArmored(keyText).keys   // for verification
 };
 return openpgp.verify(options).then((verified)=>{
  return {options, verified};
 });
 return {
  text: options.message.text,
  valid: verified.signatures[0].valid,
  error
 };