Merge pull request #2 from aoxrud-ww/patch-1

customErrors and customizable errorHandler

Author: will123195

README.md

@@ -37,25 +37,30 @@ app.use(errorHandler({ debug: true }))
 
 You may throw any of the following types of errors with an optional error `message`.
 
-### `throw validationError( message )`
+### `throw validationError( message, details )`
 
 - Appropriate for missing required fields or invalid input.
-- Sets the response status code to `400`. 
+- Sets the response status code to `400`.
 
-### `throw authRequired( message )`
+### `throw authRequired( message, details )`
 
 - Appropriate when token or authentication is missing.
-- Sets the response status code to `401`. 
+- Sets the response status code to `401`.
 
-### `throw accessDenied( message )` 
+### `throw accessDenied( message, details )`
 
 - Appropriate when the user making the request does not have permission to the resource.
-- Sets the response status code to `403`. 
+- Sets the response status code to `403`.
 
-### `throw notFound( message )`
+### `throw notFound( message, details )`
 
 - Appropriate when the requested resource does not exist.
-- Sets the response status code to `404`. 
+- Sets the response status code to `404`.
+
+
+### `throw customError( message, details, httpStatus )`
+
+- Appropriate for when custom errors are necessary
 
 ## Handling Errors
 
@@ -69,4 +74,16 @@ app.use(errorHandler({ debug: true }))
 
 ### Error Handler Options
 
-`debug` {Boolean} - returns debug output (stack trace, request data)
+- `debug` {Boolean} - (optional) returns debug output (stack trace, request data)
+- `onError` {Function} - (optional) intercept error before sending to client
+
+
+```js
+app.use(errorHandler({
+  debug: true,
+  transform: ({ err, req, res, responseBody }) => {
+    res.setHeader('X-Warning', 'Stop sending bad requests.')
+    return responseBody;
+  }
+}))
+```

dist/createError.js

@@ -3,40 +3,45 @@
 Object.defineProperty(exports, "__esModule", {
   value: true
 });
-exports.notFound = exports.accessDenied = exports.authRequired = exports.validationError = void 0;
+exports.notFound = exports.accessDenied = exports.authRequired = exports.validationError = exports.customError = void 0;
 
-// 400
-var validationError = function validationError(message) {
-  var err = new Error(message || 'Validation error.');
-  err.validationError = true;
+var customError = function customError(message, details, httpStatus) {
+  var err = new Error(message);
+  err.details = details;
+  err.httpStatus = httpStatus;
   return err;
-}; // 401
+};
 
+exports.customError = customError;
 
-exports.validationError = validationError;
+var validationError = function validationError() {
+  var message = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : 'Validation error.';
+  var details = arguments.length > 1 ? arguments[1] : undefined;
+  return customError(message, details, 400);
+};
 
-var authRequired = function authRequired(message) {
-  var err = new Error(message || 'Authentication required.');
-  err.authRequired = true;
-  return err;
-}; // 403
+exports.validationError = validationError;
 
+var authRequired = function authRequired() {
+  var message = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : 'Authentication required.';
+  var details = arguments.length > 1 ? arguments[1] : undefined;
+  return customError(message, details, 401);
+};
 
 exports.authRequired = authRequired;
 
-var accessDenied = function accessDenied(message) {
-  var err = new Error(message || 'Access denied.');
-  err.accessDenied = true;
-  return err;
-}; // 404
-
+var accessDenied = function accessDenied() {
+  var message = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : 'Access denied.';
+  var details = arguments.length > 1 ? arguments[1] : undefined;
+  return customError(message, details, 403);
+};
 
 exports.accessDenied = accessDenied;
 
-var notFound = function notFound(message) {
-  var err = new Error(message || 'Not found.');
-  err.notFound = true;
-  return err;
+var notFound = function notFound() {
+  var message = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : 'Not found.';
+  var details = arguments.length > 1 ? arguments[1] : undefined;
+  return customError(message, details, 404);
 };
 
 exports.notFound = notFound;

dist/errorHandler.js

@@ -5,32 +5,26 @@ Object.defineProperty(exports, "__esModule", {
 });
 exports["default"] = void 0;
 
+var defaultTransformer = function defaultTransformer(_ref) {
+  var err = _ref.err,
+      req = _ref.req,
+      res = _ref.res,
+      responseBody = _ref.responseBody;
+  return responseBody;
+};
+
 var _default = function _default() {
-  var _ref = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : {},
-      _ref$debug = _ref.debug,
-      debug = _ref$debug === void 0 ? false : _ref$debug;
+  var _ref2 = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : {},
+      _ref2$debug = _ref2.debug,
+      debug = _ref2$debug === void 0 ? false : _ref2$debug,
+      _ref2$transform = _ref2.transform,
+      transform = _ref2$transform === void 0 ? defaultTransformer : _ref2$transform;
 
   return function (err, req, res, next) {
-    var statusCode = 500;
-
-    if (err.validationError) {
-      statusCode = 400;
-    }
-
-    if (err.authRequired) {
-      statusCode = 401;
-    }
-
-    if (err.accessDenied) {
-      statusCode = 403;
-    }
-
-    if (err.notFound) {
-      statusCode = 404;
-    }
-
-    var error = {
-      message: err.message
+    var statusCode = err.httpStatus || 500;
+    var responseBody = {
+      message: err.message,
+      details: err.details
     };
     var stack;
 
@@ -45,7 +39,7 @@ var _default = function _default() {
     }
 
     if (debug) {
-      error.debug = {
+      responseBody.debug = {
         stack: stack,
         request: {
           method: req.method,
@@ -58,10 +52,16 @@ var _default = function _default() {
 
 
     if (err.body) {
-      error.message = 'Could not parse JSON body.';
+      responseBody.message = 'Could not parse JSON body.';
     }
 
-    res.status(statusCode).json(error);
+    responseBody = transform({
+      err: err,
+      req: req,
+      res: res,
+      responseBody: responseBody
+    });
+    res.status(statusCode).json(responseBody);
   };
 };
 

src/createError.js

@@ -1,27 +1,18 @@
-// 400
-export const validationError = (message) => {
-  const err = new Error(message || 'Validation error.')
-  err.validationError = true
-  return err
+export const customError = (message, details, httpStatus) => {
+  const err = new Error(message);
+  err.details = details;
+  err.httpStatus = httpStatus;
+  return err;
 }
 
-// 401
-export const authRequired = (message) => {
-  const err = new Error(message || 'Authentication required.')
-  err.authRequired = true
-  return err
-}
+export const validationError = (message = 'Validation error.',  details) => 
+  customError(message, details, 400)
 
-// 403
-export const accessDenied = (message) => {
-  const err = new Error(message || 'Access denied.')
-  err.accessDenied = true
-  return err
-}
+export const authRequired = (message = 'Authentication required.', details) => 
+  customError(message, details, 401)
+
+export const accessDenied = (message = 'Access denied.', details) => 
+  customError(message, details, 403);
 
-// 404
-export const notFound = (message) => {
-  const err = new Error(message || 'Not found.')
-  err.notFound = true
-  return err
-}
+export const notFound = (message = 'Not found.', details) => 
+  customError(message, details, 404);

src/errorHandler.js

@@ -1,20 +1,12 @@
-export default ({ debug = false } = {}) => (err, req, res, next) => {
-  let statusCode = 500
-  if (err.validationError) {
-    statusCode = 400
-  }
-  if (err.authRequired) {
-    statusCode = 401
-  }
-  if (err.accessDenied) {
-    statusCode = 403
-  }
-  if (err.notFound) {
-    statusCode = 404
-  }
-  const error = {
-    message: err.message
-  }
+const defaultTransformer = ({ err, req, res, responseBody }) => responseBody;
+
+export default ({ debug = false, transform = defaultTransformer } = {}) => (err, req, res, next) => {
+  const statusCode = err.httpStatus || 500
+  let responseBody = {
+    message: err.message,
+    details: err.details
+  }
+
   let stack
   if (err.stack) {
     stack = err.stack.split('\n')
@@ -24,7 +16,7 @@ export default ({ debug = false } = {}) => (err, req, res, next) => {
       .map(line => line.trim())
   }
   if (debug) {
-    error.debug = {
+    responseBody.debug = {
       stack,
       request: {
         method: req.method,
@@ -36,7 +28,8 @@ export default ({ debug = false } = {}) => (err, req, res, next) => {
   }
   // body-parser error
   if (err.body) {
-    error.message = 'Could not parse JSON body.'
+    responseBody.message = 'Could not parse JSON body.'
   }
-  res.status(statusCode).json(error)
+  responseBody = transform({ err, req, res, responseBody });
+  res.status(statusCode).json(responseBody)
 }

test/spec.js

@@ -3,13 +3,21 @@ const {
   accessDenied,
   authRequired,
   notFound,
+  customError,
   errorHandler
 } = require('..')
 
 const express = require('express')
 const supertest = require('supertest')
 
 const app = express()
+const currentTime = Date.now();
+const teapotError = () =>
+  customError("I'm a teapot", null, 418);
+const tooEarlyError = () =>
+  customError("It is too early for errors", {
+    time: currentTime
+  }, 425);
 
 app.get('/:test', (req, res, next) => {
   try {
@@ -19,6 +27,8 @@ app.get('/:test', (req, res, next) => {
       case '401': throw authRequired()
       case '403': throw accessDenied()
       case '404': throw notFound()
+      case '418': throw teapotError()
+      case '425': throw tooEarlyError()
     }
     res.json({ success: true })
   } catch (err) {
@@ -81,3 +91,22 @@ test('GET /404', done => {
     })
     .end(done)
 })
+
+test('GET /418', done => {
+  supertest(app)
+    .get('/418')
+    .expect(418)
+    .end(done)
+})
+
+
+test('GET error with details', done => {
+  supertest(app)
+    .get('/425')
+    .expect(425)
+    .expect(res => {
+      if (res.body.details.time !== currentTime)
+        throw new Error('the error.details were not provided')
+    })
+    .end(done)
+})