http-errors

Create HTTP errors for Express, Koa, Connect, etc. with ease.

Install

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

$ npm install http-errors

Example

var createError = require('http-errors')
var express = require('express')
var app = express()

app.use(function (req, res, next) {
  if (!req.user) return next(createError(401, 'Please login to view this page.'))
  next()
})

API

This is the current API, currently extracted from Koa and subject to change.

Error Properties

expose - can be used to signal if message should be sent to the client, defaulting to false when status >= 500
headers - can be an object of header names to values to be sent to the client, defaulting to undefined. When defined, the key names should all be lower-cased
message - the traditional error message, which should be kept short and all single line
status - the status code of the error, mirroring statusCode for general compatibility
statusCode - the status code of the error, defaulting to 500

createError([status], [message], [properties])

Create a new error object with the given message msg. The error object inherits from createError.HttpError.

var err = createError(404, 'This video does not exist!')

status: 500 - the status code as a number
message - the message of the error, defaulting to node's text for that status code.
properties - custom properties to attach to the object

createError([status], [error], [properties])

Extend the given error object with createError.HttpError properties. This will not alter the inheritance of the given error object, and the modified error object is the return value.

fs.readFile('foo.txt', function (err, buf) {
  if (err) {
    if (err.code === 'ENOENT') {
      var httpError = createError(404, err, { expose: false })
    } else {
      var httpError = createError(500, err)
    }
  }
})

status - the status code as a number
error - the error object to extend
properties - custom properties to attach to the object

createError.isHttpError(val)

Determine if the provided val is an HttpError. This will return true if the error inherits from the HttpError constructor of this module or matches the "duck type" for an error this module creates. All outputs from the createError factory will return true for this function, including if an non-HttpError was passed into the factory.

new createError[code || name]([msg]))