Erroran

A simple error handling middleware made for Express app. It can be used for throwing operational error in JSON response to the client. Erroran also catch all programming errors in production and throw friendly/desired error message to client.

• Installation
• Usage
  • Simple Usage
  • More Options
• Configuration
• Programming Errors
• Coming Soon
• License
• Author

Installation

This is a Node.js module available through the npm registry. Installation is done using the npm install command:

$ npm install erroran

Usage

Simple Usage

Using the Erroran class to return operational error

var express = require('express');
var { Erroran, ErroranHandler } = require('erroran');
var app = express();

app.get('/products/:id', function (req, res, next) {
    return next(
        new Erroran('You are not logged in! Please log in to get access', 401)
    );
});

// Make sure this is always your last middleware
app.use(ErroranHandler());

app.listen(5000, () => {
    console.log(`Server running in ${process.env.NODE_ENV} mode on port 5000`);
});

Alternatively, you can throw operational error like this

var express = require('express');
var { Erroran, ErroranHandler } = require('erroran');
var app = express();

app.get('/products/:id', function (req, res, next) {
    throw new Erroran(
        'You are not logged in! Please log in to get access',
        401
    );
});

// Make sure this is always your last middleware
app.use(ErroranHandler());

app.listen(5000, () => {
    console.log(`Server running in ${process.env.NODE_ENV} mode on port 5000`);
});

Sample response

{
    "status": "failed",
    "message": "You are not logged in! Please log in to get access"
}

NOTE: If you are throwing Erroran in async/await function make sure you catch the error object in catch() block and pass it to the next() function like below.

var express = require('express');
var { Erroran, ErroranHandler } = require('erroran');
var app = express();

app.get('/users/:id', async function (req, res, next) {
    try {
        var user = await User.findById(req.params.id);

        if (!user) {
            throw new Erroran('There is no user with that id', 404);
        }
    } catch (err) {
        next(err);
    }
});

// Make sure this is always your last middleware
app.use(ErroranHandler());

app.listen(5000, () => {
    console.log(`Server running in ${process.env.NODE_ENV} mode on port 5000`);
});

If you throw Erroran in a then() chain you can as well catch the error in catch() block and pass it to the next() function like below.

User.findById(req.params.id)
    .then((user) => {
        if (user.role !== 'admin') {
            throw new Erroran('You don\'t have permission to access this route', 403);
        }
    })
    .catch((err) => {
        next(err);
    });

More Options

Erroran gives more options for throwing operational errors without instantiating the Erroran class. You can throw any of the Erroran static methods below with or without string as an argument.

var { Erroran } = require('erroran');

Erroran.badRequest(); // 400 status code
Erroran.notAuthenticated(); // 401 status code
Erroran.paymentRequired(); // 402 status code
Erroran.forbidden(); // 403 status code
Erroran.notFound(); // 404 status code
Erroran.unsupportedHTTPMethod(); // 405 status code
Erroran.notAcceptable(); // 406 status code
Erroran.proxyAuthenticationRequired(); // 407 status code
Erroran.requestTimeout(); // 408 status code
Erroran.conflict(); // 409 status code
Erroran.gone(); // 410 status code
Erroran.lengthRequired(); // 411 status code
Erroran.preconditionFailed(); // 412 status code
Erroran.requestEntityTooLarge(); // 413 status code
Erroran.requestURITooLong(); // 414 status code
Erroran.unsupportedMediaType(); // 415 status code
Erroran.requestedRangeNotSatisfiable(); // 416 status code
Erroran.expectationFailed(); // 417 status code;
Erroran.internalServerError(); // 500 status code
Erroran.notImplemented(); // 501 status code
Erroran.badGateway(); // 502 status code
Erroran.serviceUnavailable(); // 503 status code
Erroran.gatewayTimout(); // 504 status code
Erroran.unsupportedHTTPVersion(); // 505 status code

You can pass your desire error message to any of the Erroran static methods as an argument, example below.

var { Erroran } = require('erroran');

throw Erroran.notAuthenticated('Please login to access this resource');

Alternatively, you can return it to the next() function

var express = require('express');
var { Erroran } = require('erroran');

var app = express();

app.get('/products/:id', function (req, res, next) {
    return next(Erroran.notAuthenticated('Please login to access this resource'));
});

Configuration

Erroran has support for MongoDB, JWT and programming error. It catches MongoDB 'CastError', 'ValidationError' and duplicate key '11000' error and also catches JWT 'JsonWebTokenError' and 'TokenExpiredError' in production.

You can configure Erroran by passing an object as an argument to the middleware like below.

var express = require('express');
var { Erroran, ErroranHandler } = require('erroran');
var app = express();

var prodErrMsg = {
    ProgrammingErrorMsg: 'My programming errors in production', // When other programming error occur in production
    CastErrorMsg: 'My MongoDB cast error message in production', // MongoDB CastError
    MongoDBDuplicateKeyErrorMsg: 'My MongoDB duplicate key error message in production', // MongoDB DuplicateKeyError 11000
    ValidationErrorMsg: 'My validation error message in production', // MongoDB ValidationError
    JsonWebTokenErrorMsg: 'My Json Web token error message in production', // JWT JsonWebTokenError
    JsonTokenExpiredErrorMsg: 'My Json Web token Expiring error message in production', // TokenExpiredError
};

// Make sure this is always your last middleware
app.use(ErroranHandler(prodErrMsg));

app.listen(5000, () => {
    console.log(`Server running in ${process.env.NODE_ENV} mode on port 5000`);
});

Erroran has default messages to throw whenever MongoDB, JWT or programming error occur in production.

Programming errors

For any programming error, Erroran will send full error stack and error message in development with 500 status code while sending 'Something went wrong, please try again later' or whatever error message you define in 'ProgrammingErrorMsg' with 500 status code in production.

All errors are sent in JSON response.

Coming soon

• Erroran will be able to send error and data to view
• Erroran will be able to log all programming errors that occur in production into a log file

License

MIT License

Author

Sylvanus Etim ([email protected])