express-error-response

Error utility and catching middleware for HTTP errors in expressjs

Installation

$ npm install express-error-response

Usage

express-error-response exposes a function which can be called to generate an error handling middleware for expressjs. It adds specific handling for RequestErrors, which are accessible via a property of the exported function.

RequestError

Class that inherits Error. Accessible via the RequestError property of the exported function. The constructor can be called with 2 parameters:

Param	Type	Description
statusCode	string \| number	The status code to be set for the response. This can be either '404' or 404 or notFound. Strings will be parsed and attempted to resolve. If unable to resolve, the status code will default to 500. The status codes either use a parsed number (which may not be NaN, -Infinity or Infinity) or the resolved code, which can be looked up in the statusCodes property of the exposed function. This can also be expanded if necessary.
body	string \| object	The body to be set for the response. This can either be a string or an object. Depending on how this is planned throughout your application, make sure you set the json property of the middleware appropriately.

Middleware

The exposed function accepts one parameter called config which can contain the following properties:

Param	Type	Description
logger	function	Any function that is called with the error object. If not passed or not a function, it is silently ignored.
json	boolean	If the error contains the body property, it will be added to the body of the response. true will respond in JSON, false will respond with a string. Default: true
catchAll	boolean	Is this the only error middleware, should it catch all errors? Setting this to true will set the status to 500 for every error that is not a RequestError. Default: false
endRequest	boolean	Should the request be ended after this middleware? true will end the request after setting the status code. Default: true
defaultFail	Mixed	Any value to respond wiht by default if the error is not a request error, or does not have a body property in general. Default: {} if config.json === true, '' if config.json === false

Sample

const express = require('express');
const err = require('express-error-response');
const {RequestError} = err;
 
const config = {
    logger: function(err){
        console.log(err)
    },
    json: true,
    catchAll: false,
    endRequest: true
};
 
const middleware = err(config);
 
const server = express();
 
// Apply your routes and middlewares
server.use('/', function(req, res) {
    throw new RequestError('badRequest', {msg: 'Your request was invalid', info: 'some other info'});
});
 
// Register the error middleware
server.use(middleware);
 
server.listen(3000, '0.0.0.0');