sequelize global error handling

globalErrorSqlz.js

// in models/index.js
if (sequelize) {
  sequelize
    .authenticate()
    .then(() => {
      console.log('Connection has been established successfully.');
    })
    .catch((err) => {
      console.error('Unable to connect to the database:', err);
    });
}

// file: globalError.js
const AppError = require('./../utils/appError');

// const handleCastErrorDB = (err) => {
//   const message = `Invalid ${err.path}: ${err.value}.`;
//   return new AppError(message, 400);
// };

const handleDuplicateFieldsDB = (err) => {
  const value = err.errors[0].message;

  const message = `Duplicate field value: ${value}. Please use another value!`;
  return new AppError(message, 400);
};

const handleValidationErrorDB = (err) => {
  const errors = Object.values(err.errors).map((el) => el.message);

  const message = `Invalid input data: ${errors.join('. ')}`;
  return new AppError(message, 400);
};

const handleJWTError = () => new AppError('Invalid token. Please log in again!', 401);

const handleJWTExpiredError = () =>
  new AppError('Your token has expired! Please log in again.', 401);

const sendErrorDev = (err, req, res) => {
  // A) API
  if (req.originalUrl.startsWith('/api')) {
    return res.status(err.statusCode).json({
      status: err.status,
      error: err,
      message: err.message,
      stack: err.stack,
    });
  }

  // B) RENDERED WEBSITE
  console.error('ERROR 💥', err);
  return res.status(err.statusCode).render('error', {
    title: 'Something went wrong!',
    msg: err.message,
  });
};

const sendErrorProd = (err, req, res) => {
  // A) API
  if (req.originalUrl.startsWith('/api')) {
    // A) Operational, trusted error: send message to client
    if (err.isOperational) {
      return res.status(err.statusCode).json({
        status: err.status,
        message: err.message,
      });
    }
    // B) Programming or other unknown error: don't leak error details
    // 1) Log error
    console.error('ERROR 💥', err);
    // 2) Send generic message
    return res.status(500).json({
      status: 'error',
      message: 'Something went very wrong!',
    });
  }

  // B) RENDERED WEBSITE
  // A) Operational, trusted error: send message to client
  if (err.isOperational) {
    return res.status(err.statusCode).render('error', {
      title: 'Something went wrong!',
      msg: err.message,
    });
  }
  // B) Programming or other unknown error: don't leak error details
  // 1) Log error
  console.error('ERROR 💥', err);
  // 2) Send generic message
  return res.status(err.statusCode).render('error', {
    title: 'Something went wrong!',
    msg: 'Please try again later.',
  });
};

module.exports = (err, req, res, next) => {
  // console.log(err.stack);

  err.statusCode = err.statusCode || 500;
  err.status = err.status || 'error';

  if (process.env.NODE_ENV === 'development') {
    sendErrorDev(err, req, res);
  } else if (process.env.NODE_ENV === 'production') {
    let error = { ...err };
    error.message = err.message;

    if (error.name === 'CastError') error = handleCastErrorDB(error);
    if (error.name === 'SequelizeUniqueConstraintError') error = handleDuplicateFieldsDB(error);
    if (error.name === 'SequelizeValidationError') error = handleValidationErrorDB(error);
    if (error.name === 'JsonWebTokenError') error = handleJWTError();
    if (error.name === 'TokenExpiredError') error = handleJWTExpiredError();

    sendErrorProd(error, req, res);
  }
};

// file: appError.js
class AppError extends Error {
  constructor(message, statusCode) {
    super(message);

    this.statusCode = statusCode;
    this.status = `${statusCode}`.startsWith('4') ? 'fail' : 'error';
    this.isOperational = true;

    Error.captureStackTrace(this, this.constructor);
  }
}

module.exports = AppError;

// file: catchAsync.js
module.exports = (fn) => {
  return (req, res, next) => {
    fn(req, res, next).catch(next);
  };
};

// in app.js
app.all('*', (req, res, next) => {
  next(new AppError(`Can't find ${req.originalUrl} on this server!`, 404));
});

app.use(globalErrorHandler);