feat(action-listener-middleware): add async error handling

Context:

- #1648 (reply in thread)

- #1648

- #547

Author: FaberVitale

packages/action-listener-middleware/README.md

@@ -102,7 +102,7 @@ Current options are:
 
 - `extra`: an optional "extra argument" that will be injected into the `listenerApi` parameter of each listener. Equivalent to [the "extra argument" in the Redux Thunk middleware](https://redux.js.org/usage/writing-logic-thunks#injecting-config-values-into-thunks).
 
-- `onError`: an optional error handler that gets called with synchronous errors raised by `listener` and `predicate`.
+- `onError`: an optional error handler that gets called with synchronous and async errors raised by `listener` and synchronous errors thrown by `predicate`.
 
 ### `listenerMiddleware.addListener(predicate, listener, options?) : Unsubscribe`
 

packages/action-listener-middleware/src/index.ts

@@ -27,6 +27,7 @@ import type {
   MiddlewarePhase,
   WithMiddlewareType,
   TakePattern,
+  ListenerErrorInfo,
 } from './types'
 
 export type {
@@ -48,7 +49,7 @@ function assertFunction(
   expected: string
 ): asserts func is (...args: unknown[]) => unknown {
   if (typeof func !== 'function') {
-    throw new TypeError(`${expected} in not a function`)
+    throw new TypeError(`${expected} is not a function`)
   }
 }
 
@@ -141,10 +142,11 @@ export const createListenerEntry: TypedCreateListenerEntry<unknown> = (
  */
 const safelyNotifyError = (
   errorHandler: ListenerErrorHandler,
-  errorToNotify: unknown
+  errorToNotify: unknown,
+  errorInfo: ListenerErrorInfo
 ): void => {
   try {
-    errorHandler(errorToNotify)
+    errorHandler(errorToNotify, errorInfo)
   } catch (errorHandlerError) {
     // We cannot let an error raised here block the listener queue.
     // The error raised here will be picked up by `window.onerror`, `process.on('error')` etc...
@@ -333,8 +335,13 @@ export function createActionListenerMiddleware<
           try {
             runListener = entry.predicate(action, currentState, originalState)
           } catch (predicateError) {
-            safelyNotifyError(onError, predicateError)
             runListener = false
+
+            safelyNotifyError(onError, predicateError, {
+              async: false,
+              raisedBy: 'predicate',
+              phase: currentPhase,
+            })
           }
         }
 
@@ -343,7 +350,7 @@ export function createActionListenerMiddleware<
         }
 
         try {
-          entry.listener(action, {
+          let promiseLikeOrUndefined = entry.listener(action, {
             ...api,
             getOriginalState,
             condition,
@@ -355,8 +362,24 @@ export function createActionListenerMiddleware<
               listenerMap.set(entry.id, entry)
             },
           })
-        } catch (listenerError) {
-          safelyNotifyError(onError, listenerError)
+
+          if (promiseLikeOrUndefined) {
+            Promise.resolve(promiseLikeOrUndefined).catch(
+              (asyncListenerError) => {
+                safelyNotifyError(onError, asyncListenerError, {
+                  async: true,
+                  raisedBy: 'listener',
+                  phase: currentPhase,
+                })
+              }
+            )
+          }
+        } catch (syncListenerError) {
+          safelyNotifyError(onError, syncListenerError, {
+            async: false,
+            raisedBy: 'listener',
+            phase: currentPhase,
+          })
         }
       }
       if (currentPhase === 'beforeReducer') {

packages/action-listener-middleware/src/tests/listenerMiddleware.test.ts

@@ -626,7 +626,7 @@ describe('createActionListenerMiddleware', () => {
     ])
   })
 
-  test('Notifies listener errors to `onError`, if provided', () => {
+  test('Notifies sync listener errors to `onError`, if provided', () => {
     const onError = jest.fn()
     middleware = createActionListenerMiddleware({
       onError,
@@ -649,7 +649,43 @@ describe('createActionListenerMiddleware', () => {
     })
 
     store.dispatch(testAction1('a'))
-    expect(onError).toBeCalledWith(listenerError)
+    expect(onError).toBeCalledWith(listenerError, {
+      async: false,
+      raisedBy: 'listener',
+      phase: 'afterReducer',
+    })
+  })
+
+  test('Notifies async listeners errors to `onError`, if provided', async () => {
+    const onError = jest.fn()
+    middleware = createActionListenerMiddleware({
+      onError,
+    })
+    reducer = jest.fn(() => ({}))
+    store = configureStore({
+      reducer,
+      middleware: (gDM) => gDM().prepend(middleware),
+    })
+
+    const listenerError = new Error('Boom!')
+    const matcher = (action: any): action is any => true
+
+    middleware.addListener({
+      matcher,
+      listener: async () => {
+        throw listenerError
+      },
+    })
+
+    store.dispatch(testAction1('a'))
+
+    await Promise.resolve()
+
+    expect(onError).toBeCalledWith(listenerError, {
+      async: true,
+      raisedBy: 'listener',
+      phase: 'afterReducer',
+    })
   })
 
   test('take resolves to the tuple [A, CurrentState, PreviousState] when the predicate matches the action', (done) => {

packages/action-listener-middleware/src/types.ts

@@ -83,7 +83,7 @@ export type ActionListener<
   A extends AnyAction,
   S,
   D extends Dispatch<AnyAction>
-> = (action: A, api: ActionListenerMiddlewareAPI<S, D>) => void
+> = (action: A, api: ActionListenerMiddlewareAPI<S, D>) => void | Promise<void>
 
 export interface ListenerErrorHandler {
   (error: unknown): void
@@ -317,3 +317,47 @@ export type ListenerPredicateGuardedActionType<T> = T extends ListenerPredicate<
 >
   ? Action
   : never
+
+export type SyncActionListener<
+  A extends AnyAction,
+  S,
+  D extends Dispatch<AnyAction>
+> = (action: A, api: ActionListenerMiddlewareAPI<S, D>) => void
+
+export type AsyncActionListener<
+  A extends AnyAction,
+  S,
+  D extends Dispatch<AnyAction>
+> = (action: A, api: ActionListenerMiddlewareAPI<S, D>) => Promise<void>
+
+/**
+ * Additional infos regarding the error raised.
+ */
+export interface ListenerErrorInfo {
+  async: boolean
+  /**
+   * Which function has generated the exception.
+   */
+  raisedBy: 'listener' | 'predicate'
+  /**
+   * When the function that has raised the error has been called.
+   */
+  phase: MiddlewarePhase
+}
+
+/**
+ * Gets notified with synchronous and asynchronous errors raised by `listeners` or `predicates`.
+ * @param error The thrown error.
+ * @param errorInfo Additional information regarding the thrown error.
+ */
+export interface ListenerErrorHandler {
+  (error: unknown, errorInfo: ListenerErrorInfo): void
+}
+
+export interface CreateListenerMiddlewareOptions<ExtraArgument = unknown> {
+  extra?: ExtraArgument
+  /**
+   * Receives synchronous and asynchronous errors that are raised by `listener` and `listenerOption.predicate`.
+   */
+  onError?: ListenerErrorHandler
+}