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http-error-handler

Automatically handles uncaught errors that contain the properties statusCode (number) and message (string) and creates a proper HTTP response for them (using the message and the status code provided by the error object). Additionally, support for the property expose is included with a default value of statusCode < 500. We recommend generating these HTTP errors with the npm module http-errors. When manually catching and setting errors with statusCode >= 500 setting {expose: true} is needed for them to be handled.

This middleware should be set as the last error handler unless you also want to register the http-response-serializer. If so, this middleware should come second-last and the http-response-serializer should come last.

Install

To install this middleware you can use NPM:

npm install --save @middy/http-error-handler

Options

  • logger (defaults to console.error) - a logging function that is invoked with the current error as an argument. You can pass false if you don't want the logging to happen.
  • fallbackMessage (default to null) - When non-http errors occur you can catch them by setting a fallback message to be used. These will be returned with a 500 status code.

Sample usage

import middy from '@middy/core'
import httpErrorHandler from '@middy/http-error-handler'

const handler = middy((event, context) => {
throw new createError.UnprocessableEntity()
})

handler
.use(httpErrorHandler())

// when Lambda runs the handler...
handler({}, {}, (_, response) => {
t.deepEqual(response,{
statusCode: 422,
body: 'Unprocessable Entity'
})
})