misc: Warn user when beforeSend doesnt return an event or null (#1635)

Author: kamilogorek

CHANGELOG.md

@@ -2,35 +2,35 @@
 
 ## Unreleased
 
-- [all] ref: Use Mocha v4 instead of v5, as it's not supporting IE10
-- [hub] Scope level overwrites level on the event
 - [hub] fix: Scope level overwrites level on the event
-- [utils] ref: implemented includes, assign and isNaN polyfills
-- [core] ref: Check for node-env first and return more accurate global object
-- [core] ref: Remove Repo interface and repos attribute from Event
-- [core] feat: getRequestheaders should handle legacy DSNs
 - [core] fix: correct sampleRate behaviour
 - [core] feat: RewriteFrames pluggable integration
+- [core] feat: Introduce stringify and debugger options in Debug integration
+- [core] feat: getRequestheaders should handle legacy DSNs
+- [core] ref: Check for node-env first and return more accurate global object
+- [core] ref: Remove Repo interface and repos attribute from Event
 - [core] ref: Check for node-env first and return more accurate global object
 - [core] ref: Remove Repo interface and repos attribute from Event
 - [core] ref: Rewrite RequestBuffer using Array instead of Set for IE10/11
-- [core] feat: Introduce stringify and debugger options in Debug integration
-- [browser] ref: Include md5 lib and transcript it to TypeScript
+- [core] misc: Warn user when beforeSend doesnt return an event or null
+- [browser] fix: Change loader to use getAttribute instead of dataset
+- [browser] fix: Remove trailing commas from loader for IE10/11
 - [browser] feat: Better mechanism detection in TraceKit
+- [browser] ref: Include md5 lib and transcript it to TypeScript
 - [browser] ref: Remove default transaction from browser
 - [browser] ref: Include md5 lib and transcript it to TypeScript
-- [browser] test: Run integration tests on SauceLabs
-- [browser] test: Fix all integration tests in IE10/11 and Android browsers
 - [browser] ref: Remove redundant debug.ts file from browser integrations
 - [browser] ref: Remove all trailing commas from integration tests cuz IE10/11
-- [browser] fix: Change loader to use getAttribute instead of dataset
-- [browser] fix: Remove trailing commas from loader for IE10/11
+- [browser] test: Run integration tests on SauceLabs
+- [browser] test: Fix all integration tests in IE10/11 and Android browsers
 - [browser] test: Store breadcrumbs in the global variable in integration tests
 - [browser] test: Update polyfills for integration tests
 - [browser] test: Stop running raven-js saucelabs tests in favour of @sentry/browser
 - [node] feat: Transactions handling for RequestHandler in Express/Hapi
 - [node] feat: Allow requestHandler to be configured
 - [node] feat: Make node transactions a pluggable integration with tests 
+- [utils] ref: implemented includes, assign and isNaN polyfills
+- [build] ref: Use Mocha v4 instead of v5, as it's not supporting IE10
 
 ## 4.0.6
 

packages/core/src/baseclient.ts

@@ -15,6 +15,7 @@ import { truncate } from '@sentry/utils/string';
 import { BackendClass } from './basebackend';
 import { Dsn } from './dsn';
 import { Backend, Client, Options } from './interfaces';
+import { logger } from './logger';
 
 /** JSDoc */
 interface ExtensibleConsole extends Console {
@@ -368,6 +369,9 @@ export abstract class BaseClient<B extends Backend, O extends Options> implement
       const isInternalException = hint && hint.data && (hint.data as { [key: string]: any }).__sentry__ === true;
       if (!isInternalException && beforeSend) {
         finalEvent = await beforeSend(prepared, hint);
+        if ((typeof finalEvent as any) === 'undefined') {
+          logger.error('`beforeSend` method has to return `null` or a valid event');
+        }
       }
     } catch (exception) {
       forget(