_error.js

// NOTE(brentvatne):
// This is the default Sentry error page provided by https://github.com/vercel/next.js/tree/canary/examples/with-sentry/

import * as Sentry from '@sentry/react';
import Error from 'next/error';
import React from 'react';

import ErrorState from '../components/ErrorState';

const MyError = ({ statusCode, hasGetInitialPropsRun, err }) => {
  if (!hasGetInitialPropsRun && err) {
    // getInitialProps is not called in case of
    // https://github.com/zeit/next.js/issues/8592. As a workaround, we pass
    // err via _app.js so it can be captured
    Sentry.captureException(err);
  }

  return <ErrorState statusCode={statusCode} />;
};

MyError.getInitialProps = async ({ res, err, asPath }) => {
  const errorInitialProps = await Error.getInitialProps({ res, err });

  // Workaround for https://github.com/zeit/next.js/issues/8592, mark when
  // getInitialProps has run
  errorInitialProps.hasGetInitialPropsRun = true;

  if (res) {
    // Running on the server, the response object is available.
    //
    // Next.js will pass an err on the server if a page's `getInitialProps`
    // threw or returned a Promise that rejected
    if (err) {
      Sentry.captureException(err);
      return errorInitialProps;
    }
  } else {
    // Running on the client (browser).
    //
    // Next.js will provide an err if:
    //
    //  - a page's `getInitialProps` threw or returned a Promise that rejected
    //  - an exception was thrown somewhere in the React lifecycle (render,
    //    componentDidMount, etc) that was caught by Next.js's React Error
    //    Boundary. Read more about what types of exceptions are caught by Error
    //    Boundaries: https://reactjs.org/docs/error-boundaries.html
    if (err) {
      Sentry.captureException(err);
      return errorInitialProps;
    }
  }

  // If this point is reached, getInitialProps was called without any
  // information about what the error might be. This is unexpected and may
  // indicate a bug introduced in Next.js, so record it in Sentry
  // Sentry.captureException(new Error(`_error.js getInitialProps missing data at path: ${asPath}`));

  return errorInitialProps;
};

export default MyError;