Decode a Json Web Token and add dates that a human understands.

jwt.js

#!/usr/bin/env node

const jwt = require('jsonwebtoken')

const token = jwt.decode(process.argv[2])
const output = {
  token,
  issued: new Date(1000*token.iat).toLocaleString(),
  expires: new Date(1000*token.exp).toLocaleString(),
}

console.log(JSON.stringify(output, null, 2))