Express error handler failed to catch the validation error

Question

Express error handler failed to catch the validation error

I have a field type in my mongoose schema that is required. I've implemented a custom error handler in express like this:

const notFound = (req, res, next) => {
  const error = new Error(`Not found-${req.originalUrl}`);
  res.status(404);
  next(error);
};

const errorHandler = (err, req, res, next) => {
  
  const statusCode = res.statusCode === 200 ? 500 : res.statusCode;
  res.status(statusCode);
  res.json({
    message: err.message,
    stack: process.env.NODE_ENV === 'production' ? null : err.stack,
  });
};

I've added the error handlers to the end of my server.js file:

app.use(notFound);
app.use(errorHandler);

However, when testing the route that posts an entry using Postman, the request gets stuck without any response. In the terminal, I see an error stating

UnhandledPromiseRejectionWarning: ValidationError: ...

Shouldn't my custom error handler catch this error?

node.js express mongoose

Answer 1

Answer №1

Ensure that when executing a mongoose action, you are properly handling and forwarding any errors to your middleware for processing.

One way to accomplish this is by implementing code similar to the following:

example.findById(req.id, async function(err, foundRecord){
  if(err) {
    next(err);
  } else {
    ....
  }
});

Please inform me if this solution resolves your issue.

Answer 2

Ensure that when executing a mongoose action, you are properly handling and forwarding any errors to your middleware for processing.

One way to accomplish this is by implementing code similar to the following:

example.findById(req.id, async function(err, foundRecord){
  if(err) {
    next(err);
  } else {
    ....
  }
});

Please inform me if this solution resolves your issue.

Answer 3

Answer №2

Try implementing a simple HttpError by following these steps:

Create a file named HttpError.js:


class HttpError extends Error {
    constructor(statusCode, message = 'Internal Server Error') {
        super(message);
        this.statusCode = statusCode;
        this.isSuccess = false;
        this.isError = true;
        this.errorMessage = message;
        this.data = null;
    }
}

module.exports.HttpError = HttpError;

You can create an example like: NotFoundError extending HttpError:

const { HttpError } = require('../HttpError');
class NotFoundError extends HttpError {
    constructor(message = 'Not Found') {
        super(404, message);
    }
}

module.exports.NotFoundError = NotFoundError;

In your app.js, you can handle errors as shown below:

// Handling notFoundError
app.use((req, res, next) => { throw new NotFoundError() });

// Handling unexpected errors or other errors
app.use((error, req, res, next) => {
    res.status(error.statusCode || 500).send(error);
})

If you prefer Indonesian language for tutorials ("But you don't have to listen, just understand the concept"), check out these links:

Handle Express Error: https://www.youtube.com/watch?v=GwS6KJmO9w8&list=PLREvIK3N7Ga6F669gbDCDMwrn37Uq32-O&index=13
Handle HttpError: https://www.youtube.com/watch?v=VoorNGvDypE&list=PLREvIK3N7Ga6F669gbDCDMwrn37Uq32-O&index=14

For example codes, visit this Github repository: https://github.com/12bedeveloper/basic-express

Keep learning and improving your coding skills.

Answer 4

Try implementing a simple HttpError by following these steps:

Create a file named HttpError.js:


class HttpError extends Error {
    constructor(statusCode, message = 'Internal Server Error') {
        super(message);
        this.statusCode = statusCode;
        this.isSuccess = false;
        this.isError = true;
        this.errorMessage = message;
        this.data = null;
    }
}

module.exports.HttpError = HttpError;

You can create an example like: NotFoundError extending HttpError:

const { HttpError } = require('../HttpError');
class NotFoundError extends HttpError {
    constructor(message = 'Not Found') {
        super(404, message);
    }
}

module.exports.NotFoundError = NotFoundError;

In your app.js, you can handle errors as shown below:

// Handling notFoundError
app.use((req, res, next) => { throw new NotFoundError() });

// Handling unexpected errors or other errors
app.use((error, req, res, next) => {
    res.status(error.statusCode || 500).send(error);
})

If you prefer Indonesian language for tutorials ("But you don't have to listen, just understand the concept"), check out these links:

Handle Express Error: https://www.youtube.com/watch?v=GwS6KJmO9w8&list=PLREvIK3N7Ga6F669gbDCDMwrn37Uq32-O&index=13
Handle HttpError: https://www.youtube.com/watch?v=VoorNGvDypE&list=PLREvIK3N7Ga6F669gbDCDMwrn37Uq32-O&index=14

For example codes, visit this Github repository: https://github.com/12bedeveloper/basic-express

Keep learning and improving your coding skills.

Express error handler failed to catch the validation error

Answer №1

Answer №2

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