sos-nextjs/pages/_error.js

import React from 'react'
import getConfig from 'next/config'

const {publicRuntimeConfig} = getConfig()

const ErrorPage = ({error}) => {
  const env = publicRuntimeConfig.SOS_ENV
  if (!error)
    return (
      <>
        <h2>Not Found</h2>
        <p>This page was not found</p>
      </>
    )

  return (
    <>
      <h2>{error.name}</h2>
      <p>{error.message}</p>
      {env === 'development' && (
        <>
          {error.stack && (
            <p>
              <pre>
                {error.stack}
              </pre>
            </p>
          )}
          <p>
            <pre>
              {JSON.stringify(error, null, 2)}
            </pre>
          </p>
        </>
      )}
    </>
  )
}

ErrorPage.getInitialProps = ({ctx: {err, req, res}}) => {
  if(!err) return {error: null}

  if(res)
    err.status = res.statusCode

  return { error: err }
}

export default ErrorPage