ProgBlog/app/config/error-handlers.js

'use strict';

// -----------------------------------------------------------------------------
// Error handlers
// -----------------------------------------------------------------------------

const container = require('../Container');
const app = container.get('app');
const HTTP_CODE_MAP = require('http').STATUS_CODES;
const errors = require('errors');
const negotiate = require('express-negotiate');

let errorHandlers = new Set([

	function handle404(req, res, next) {
		if (! req.route) {
			// if no route matches, send a 404
			let err = new errors.Http404Error();
			return next(err);
		}
	},

	function handle400Errors(err, req, res, next) {
		if (err instanceof negotiate.NotAcceptable) {
			// if no content type matches, send a 406
			err = new errors.Http406Error();
		}

		return next(err);
	},

	// general error handler
	function handleError(err, req, res, next) {
		let httpStatus = err.status || 500;
		let message = err.message || HTTP_CODE_MAP[httpStatus];

		res.status(httpStatus);

		let output = {
			status: httpStatus,
			message: message,
		};

		// Show stack trace in development environment
		if (app.get('env') === 'development') {
			output.error = err;
		}

		// Send html or json depending on client accept header
		req.negotiate({
			html: () => {
				res.render('error', {
					title: `${err.status} ${err.message}`,
					error: output,
				});
			},

			'application/json': () => {
				res.json(output);
			},
		});
	},
]);

module.exports = errorHandlers;