CODEWITHSUNDEEP
node.jsexpresserror-handling
Rosan Paudel
Rosan Paudel

Reputation: 170

Custom Error Handler not working in NodeJs Express

I was studying about error handeling in express and I defined one. It works fine for non async functions. But when it comes to async function the app just breaks.

app.get("/products/:id", async (req, res, next) => {
  const { id } = req.params;
  const product = await Product.findById(id);
  if (!product) {
    return next(new AppError());
  }
  res.render("products/show", { product });
});

I have put the error handler at the bottom of the app like this:

app.use((err, req, res, next) => {
  const { status = 500, message = "something went wrong" } = err;
  res.status(status).send(message);
});

My custom Error Class:

class AppError extends Error {
  constructor(message, status) {
    super();
    this.message = message;
    this.status = status;
  }
}

module.exports = AppError;

Upvotes: 0

Views: 1275

Answers (1)

Matt1234
Matt1234

Reputation: 36

I believe your router doesn't know what to do when it the await fails for whatever reason. You can use this catchAsync I made below but you can also do a try catch statement around your code so it catches the error and goes onto the next task.

The try/catch could look something like this

app.get("/products/:id", async (req, res, next) => {
  try{
    const { id } = req.params;
    const product = await Product.findById(id);
    res.render("products/show", { product });
    
  } catch(err) {
    return next(new AppError());
  }
});

This is my catch async function that you can use.

module.exports = func => {
    return (req, res, next) => {
        func(req, res, next).catch(next);
    }
}

Please let me know if this doesn't solve the problem

Upvotes: 1

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