http-error-middleware

http-error-middleware is a package that simplifies error handling in Express applications. It provides an easy way to generate and manage specific HTTP errors using middleware, making your code clearer and ensuring a consistent structure for error responses.

This package allows you to throw errors with specific HTTP status codes and custom messages, then handle them centrally in your application using a single middleware.

Installation

You can install the package from npm using the following command:

npm install http-error-middleware

Basic Usage

Set Up Middleware in Your Express Application

First, you need to import and use the middleware provided by http-error-middleware in your Express app.

import express from 'express'
// Import the package
import { httpErrorMiddleware } from 'http-error-middleware'

const app = express()

// Define your app routes.
app.get('/', (req, res) => {
  res.status(200).json({ message: 'Hello world' })
})

// Use the middleware to handle errors.
app.use(httpErrorMiddleware())
// Other middleware for handling errors can go here.

// Start the server.
app.listen(3000, () => {
  console.log('Server running')
})

httpErrorMiddleware settings

The middleware offers some configurations to customize the error response, which are optional.

import express from 'express'

import { httpErrorMiddleware } from 'http-error-middleware'

const app = express()
//Other Express app config

app.use(httpErrorMiddleware({
  destructure: false,
  statusCodeOnResponse: false
}))

• If you want the error details to be placed at the root of the response body, set the "destructure" flag to true.

• If you want the status code sent to be in the response body, set the "statusCodeOnResponse" flag to true.

The default settings is as follows:

{
  "destructure": false,
  "statusCodeOnResponse": true
}

Throw Errors Where You Need Them

You can throw HTTP errors anywhere in your application using the HttpError class provided by the package. Here's a simple example to throw a 400 Bad Request error.

import { HttpError } from 'http-error-middleware'

if (condition) throw HttpError.badRequest('Email and/or password are wrong')

This code will throw an error that gets handled by the middleware, and the response will look like this:

{
  "message": "Email and/or password are wrong",
  "statusCode": 400 // This property will be removed this if you set the "statusCodeOnResponse" flag to false.
}

Errors with Additional Details

If you need to send more details with the error (e.g., information about which form field is incorrect), you can do it like this:

import { HttpError } from 'http-error-middleware'

if (condition) HttpError.badRequest('Email and/or password are wrong', { fieldName: "Error message", ...moreErrors })

This will generate a response with additional error details:

{
  "message": "Email and/or password are wrong",
  "details": {
    "fieldName": "Error message",
    "fieldName2": "Error message"
  },
  "statusCode": 400 // This property will be removed this if you set the "statusCodeOnResponse" flag to false.
}

If you have the "destructure" flag set, the message will be displayed like this:

{
  "message": "Email and/or password are wrong",
  "fieldName": "Error message",
  "fieldName2": "Error message",
  "statusCode": 400 // This property will be removed this if you set the "statusCodeOnResponse" flag to false.
}

Available HTTP Error Methods

The package provides methods to generate common HTTP errors with specific status codes. Here are the available methods:

Client Errors (4xx)

• HttpError.badRequest(message: string, details?: object)

  • Throws a 400 Bad Request error with the provided message and optional details.

• HttpError.unauthorized(message: string, details?: object)

  • Throws a 401 Unauthorized error with the provided message and optional details.

• HttpError.paymentRequired(message: string, details?: object)

  • Throws a 402 Payment Required error with the provided message and optional details.

• HttpError.forbidden(message: string, details?: object)

  • Throws a 403 Forbidden error with the provided message and optional details.

• HttpError.notFound(message: string, details?: object)

  • Throws a 404 Not Found error with the provided message and optional details.

• HttpError.methodNotAllowed(message: string, details?: object)

  • Throws a 405 Method Not Allowed error with the provided message and optional details.

• HttpError.notAcceptable(message: string, details?: object)

  • Throws a 406 Not Acceptable error with the provided message and optional details.

• HttpError.proxyAuthenticationRequired(message: string, details?: object)

  • Throws a 407 Proxy Authentication Required error with the provided message and optional details.

• HttpError.requestTimeOut(message: string, details?: object)

  • Throws a 408 Request Timeout error with the provided message and optional details.

• HttpError.conflict(message: string, details?: object)

  • Throws a 409 Conflict error with the provided message and optional details.

Server Errors (5xx)

• HttpError.internalServerError(message: string, details?: object)

  • Throws a 500 Internal Server Error with the provided message and optional details.

• HttpError.notImplemented(message: string, details?: object)

  • Throws a 501 Not Implemented error with the provided message and optional details.

• HttpError.badGateway(message: string, details?: object)

  • Throws a 502 Bad Gateway error with the provided message and optional details.

• HttpError.serviceUnavailable(message: string, details?: object)

  • Throws a 503 Service Unavailable error with the provided message and optional details.

• HttpError.gatewayTimeOut(message: string, details?: object)

  • Throws a 504 Gateway Timeout error with the provided message and optional details.

Custom Error

• HttpError.custom(message: string, statusCode: number, details?: object)
  • Throws a custom error with a specified statusCode (for errors not covered by the predefined methods) and optional details.

Each of these methods generates a response with an appropriate HTTP status code, a message, and optionally, additional details.

Benefits

Consistency: Centralize error handling in a single middleware. Clarity: Easily create and throw HTTP errors with clear and specific messages. Extensibility: Add additional details to errors to provide more context, such as information about specific fields.