From 129991fcfd4e2faf66ae1b3f334fcf39d0378bf5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Fredrik=20Adel=C3=B6w?= <freben@gmail.com>
Date: Mon, 4 May 2020 16:34:17 +0200
Subject: [PATCH] Even denser errors

---
 packages/backend-common/src/errors.ts         | 60 +++++++------------
 .../src/middleware/errorHandler.test.ts       | 12 ++--
 .../src/middleware/errorHandler.ts            |  4 +-
 packages/backend-common/tsconfig.json         |  2 +-
 4 files changed, 29 insertions(+), 49 deletions(-)

diff --git a/packages/backend-common/src/errors.ts b/packages/backend-common/src/errors.ts
index c3cf53453e..34a605a576 100644
--- a/packages/backend-common/src/errors.ts
+++ b/packages/backend-common/src/errors.ts
@@ -28,51 +28,39 @@
 class CustomErrorBase extends Error {
   readonly cause?: Error;
 
-  constructor(constructor: Function, message?: string, cause?: Error) {
-    super(message);
-    Object.setPrototypeOf(this, constructor.prototype);
-    Error.captureStackTrace(this, constructor);
-    this.name = this.constructor.name;
-    this.cause = cause;
-  }
-
-  toString() {
-    let result = super.toString();
-
-    if (this.cause) {
-      result += `; caused by ${this.cause.toString()}`;
+  constructor(message?: string, cause?: Error) {
+    let fullMessage = message;
+    if (cause) {
+      if (fullMessage) {
+        fullMessage += `; caused by ${cause}`;
+      } else {
+        fullMessage = `caused by ${cause}`;
+      }
     }
 
-    return result;
+    super(fullMessage);
+
+    Error.captureStackTrace(this, this.constructor);
+
+    this.name = this.constructor.name;
+    this.cause = cause;
   }
 }
 
 /**
  * The request is malformed and cannot be processed.
  */
-export class BadRequestError extends CustomErrorBase {
-  constructor(message?: string, cause?: Error) {
-    super(BadRequestError, message, cause);
-  }
-}
+export class BadRequestError extends CustomErrorBase {}
 
 /**
  * The request requires authentication, which was not properly supplied.
  */
-export class UnauthenticatedError extends CustomErrorBase {
-  constructor(message?: string, cause?: Error) {
-    super(UnauthenticatedError, message, cause);
-  }
-}
+export class AuthenticationError extends CustomErrorBase {}
 
 /**
- * The authenticated caller is not permitted to perform this request.
+ * The authenticated caller is not allowed to perform this request.
  */
-export class ForbiddenError extends CustomErrorBase {
-  constructor(message?: string, cause?: Error) {
-    super(ForbiddenError, message, cause);
-  }
-}
+export class NotAllowedError extends CustomErrorBase {}
 
 /**
  * The requested resource could not be found.
@@ -80,18 +68,10 @@ export class ForbiddenError extends CustomErrorBase {
  * Note that this error usually is used to indicate that an entity with a given
  * ID does not exist, rather than signalling that an entire route is missing.
  */
-export class NotFoundError extends CustomErrorBase {
-  constructor(message?: string, cause?: Error) {
-    super(NotFoundError, message, cause);
-  }
-}
+export class NotFoundError extends CustomErrorBase {}
 
 /**
  * The request could not complete due to a conflict in the current state of the
  * resource.
  */
-export class ConflictError extends CustomErrorBase {
-  constructor(message?: string, cause?: Error) {
-    super(ConflictError, message, cause);
-  }
-}
+export class ConflictError extends CustomErrorBase {}
diff --git a/packages/backend-common/src/middleware/errorHandler.test.ts b/packages/backend-common/src/middleware/errorHandler.test.ts
index 8f4a8cfea4..d282ccb99b 100644
--- a/packages/backend-common/src/middleware/errorHandler.test.ts
+++ b/packages/backend-common/src/middleware/errorHandler.test.ts
@@ -52,11 +52,11 @@ describe('errorHandler', () => {
     app.use('/BadRequestError', () => {
       throw new errors.BadRequestError();
     });
-    app.use('/UnauthenticatedError', () => {
-      throw new errors.UnauthenticatedError();
+    app.use('/AuthenticationError', () => {
+      throw new errors.AuthenticationError();
     });
-    app.use('/ForbiddenError', () => {
-      throw new errors.ForbiddenError();
+    app.use('/NotAllowedError', () => {
+      throw new errors.NotAllowedError();
     });
     app.use('/NotFoundError', () => {
       throw new errors.NotFoundError();
@@ -68,8 +68,8 @@ describe('errorHandler', () => {
 
     const r = request(app);
     expect((await r.get('/BadRequestError')).status).toBe(400);
-    expect((await r.get('/UnauthenticatedError')).status).toBe(401);
-    expect((await r.get('/ForbiddenError')).status).toBe(403);
+    expect((await r.get('/AuthenticationError')).status).toBe(401);
+    expect((await r.get('/NotAllowedError')).status).toBe(403);
     expect((await r.get('/NotFoundError')).status).toBe(404);
     expect((await r.get('/ConflictError')).status).toBe(409);
   });
diff --git a/packages/backend-common/src/middleware/errorHandler.ts b/packages/backend-common/src/middleware/errorHandler.ts
index eb1b0597a7..43782e4d7f 100644
--- a/packages/backend-common/src/middleware/errorHandler.ts
+++ b/packages/backend-common/src/middleware/errorHandler.ts
@@ -81,9 +81,9 @@ function getStatusCode(error: Error): number {
   switch (error.name) {
     case errors.BadRequestError.name:
       return 400;
-    case errors.UnauthenticatedError.name:
+    case errors.AuthenticationError.name:
       return 401;
-    case errors.ForbiddenError.name:
+    case errors.NotAllowedError.name:
       return 403;
     case errors.NotFoundError.name:
       return 404;
diff --git a/packages/backend-common/tsconfig.json b/packages/backend-common/tsconfig.json
index b463ac102f..6d7ca21afa 100644
--- a/packages/backend-common/tsconfig.json
+++ b/packages/backend-common/tsconfig.json
@@ -7,7 +7,7 @@
     "sourceMap": true,
     "declaration": true,
     "strict": true,
-    "target": "es5",
+    "target": "ES2019",
     "module": "commonjs",
     "esModuleInterop": true,
     "types": ["node", "jest"]