Only performs basic validation, not verification. Returns object original JWT, unencrypted and parsed payload, and valid boolean.

validateJWT.js

function validateJWT(jwt) {
  let payload = {}, valid = false
  try {
    [, payload] = jwt.split('.').slice(0,2).map(p => JSON.parse(atob(p)))
    valid = true
  } catch (error) {}
  return { jwt, payload, valid }
}