CODEWITHSUNDEEP
node.jsexpress
rsilva
rsilva

Reputation: 270

throw error code with 'return next(err);'

How do I go about specifying the error code with a return next(err) statement so that I can display it in my catch all middleware?

var express = require('express');
var exphbs  = require('express-handlebars');
var fs = require("fs");
var app = express();

app.engine('handlebars', exphbs({defaultLayout: 'main'}));
app.set('view engine', 'handlebars');

app.get('/', function(req, res, next) {

    // simulate 404 error
    fs.readFile("foo.txt", "utf8", function(error, data) {
      if(error) {
        next(new Error('Aiiii caramba'));
      }
    });

});

/* Error Handling (gotta catch 'em all) */
app.use(function(err, req, res, next) {
    res.status(err.status || 500)
    .render('error', { 
    status: req.status,
    error: err
  });
});

app.listen(3000, function() {
    console.log('Listening...');
})

The Error object doesn't acccept an argument for error code. I also tried setting the response status before returning next... to no avail.

res.status(404); return next(err);

No matter what I do, I get error 500.

Thank you in advance for your time.

Upvotes: 3

Views: 1253

Answers (2)

Ilio Catallo
Ilio Catallo

Reputation: 3180

There's no reason why Error should have a status property. If you want it, you have to craft your own error and let it inherit from Error.

In ES6 this can be done as follows:

class NotFound extends Error {
    constructor(message) {
        super(message);
        this.status = 404;
    }
}

If you are stuck with ES5, you can instead use the util module provided with node:

var util = require('util');

function NotFound(message) {
    Error.call(this);
    this.message = message;
    this.status = 404;
}

util.inherits(NotFound, Error);

Now, you can throw your custom error as next(new NotFound('Aiiii caramba'));. Arguably, NotFound('Aiiii caramba') expresses in a clear way the kind of encountered error.

Upvotes: 3

Nir Levy
Nir Levy

Reputation: 12953

the problem is with your error handling after the middlewares:

/* Error Handling (gotta catch 'em all) */
app.use(function(err, req, res, next) {
    res.status(err.status || 500)
    .render('error', { 
    status: req.status,
    error: err
  });
});

you have there the line: res.status(err.status || 500) and since your error object does not have a status field, it is always assigned to 500

Upvotes: 1

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