ensure all actions have a string type

Author: EskiMojo14

packages/toolkit/src/createAction.ts

@@ -84,7 +84,7 @@ export type _ActionCreatorWithPreparedPayload<
  */
 export interface BaseActionCreator<P, T extends string, M = never, E = never> {
   type: T
-  match: (action: Action<unknown>) => action is PayloadAction<P, T, M, E>
+  match: (action: Action<string>) => action is PayloadAction<P, T, M, E>
 }
 
 /**
@@ -290,8 +290,12 @@ export function createAction(type: string, prepareAction?: Function): any {
 /**
  * Returns true if value is a plain object with a `type` property.
  */
-export function isAction(action: unknown): action is Action<unknown> {
-  return isPlainObject(action) && 'type' in action
+export function isAction(action: unknown): action is Action<string> {
+  return (
+    isPlainObject(action) &&
+    'type' in action &&
+    typeof (action as Record<'type', unknown>).type === 'string'
+  )
 }
 
 /**
@@ -317,11 +321,7 @@ export function isFSA(action: unknown): action is {
   error?: unknown
   meta?: unknown
 } {
-  return (
-    isAction(action) &&
-    typeof action.type === 'string' &&
-    Object.keys(action).every(isValidKey)
-  )
+  return isAction(action) && Object.keys(action).every(isValidKey)
 }
 
 function isValidKey(key: string) {

packages/toolkit/src/tests/createAction.typetest.tsx

@@ -258,7 +258,7 @@ import { expectType } from './helpers'
   // simple use case
   {
     const actionCreator = createAction<string, 'test'>('test')
-    const x: Action<unknown> = {} as any
+    const x: Action<string> = {} as any
     if (actionCreator.match(x)) {
       expectType<'test'>(x.type)
       expectType<string>(x.payload)
@@ -273,7 +273,7 @@ import { expectType } from './helpers'
   // special case: optional argument
   {
     const actionCreator = createAction<string | undefined, 'test'>('test')
-    const x: Action<unknown> = {} as any
+    const x: Action<string> = {} as any
     if (actionCreator.match(x)) {
       expectType<'test'>(x.type)
       expectType<string | undefined>(x.payload)
@@ -283,7 +283,7 @@ import { expectType } from './helpers'
   // special case: without argument
   {
     const actionCreator = createAction('test')
-    const x: Action<unknown> = {} as any
+    const x: Action<string> = {} as any
     if (actionCreator.match(x)) {
       expectType<'test'>(x.type)
       // @ts-expect-error
@@ -298,7 +298,7 @@ import { expectType } from './helpers'
       meta: '',
       error: false,
     }))
-    const x: Action<unknown> = {} as any
+    const x: Action<string> = {} as any
     if (actionCreator.match(x)) {
       expectType<'test'>(x.type)
       expectType<string>(x.payload)
@@ -315,7 +315,7 @@ import { expectType } from './helpers'
   // potential use: as array filter
   {
     const actionCreator = createAction<string, 'test'>('test')
-    const x: Array<Action<unknown>> = []
+    const x: Array<Action<string>> = []
     expectType<Array<PayloadAction<string, 'test'>>>(
       x.filter(actionCreator.match)
     )

packages/toolkit/src/tests/createSlice.typetest.ts

@@ -386,13 +386,13 @@ const value = actionCreators.anyKey
     },
   })
 
-  const x: Action<unknown> = {} as any
+  const x: Action<string> = {} as any
   if (mySlice.actions.setName.match(x)) {
     expectType<'name/setName'>(x.type)
     expectType<string>(x.payload)
   } else {
     // @ts-expect-error
-    expectType<string>(x.type)
+    expectType<'name/setName'>(x.type)
     // @ts-expect-error
     expectType<string>(x.payload)
   }

packages/toolkit/src/tests/serializableStateInvariantMiddleware.test.ts

@@ -103,15 +103,16 @@ describe('serializableStateInvariantMiddleware', () => {
       middleware: [serializableStateInvariantMiddleware],
     })
 
-    const type = Symbol.for('SOME_CONSTANT')
-    const dispatchedAction = { type }
+    const symbol = Symbol.for('SOME_CONSTANT')
+    const dispatchedAction = { type: 'an-action', payload: symbol }
 
     store.dispatch(dispatchedAction)
 
     expect(getLog().log).toMatchInlineSnapshot(`
-      "A non-serializable value was detected in an action, in the path: \`type\`. Value: Symbol(SOME_CONSTANT) 
+      "A non-serializable value was detected in an action, in the path: \`payload\`. Value: Symbol(SOME_CONSTANT) 
       Take a look at the logic that dispatched this action:  Object {
-        \\"type\\": Symbol(SOME_CONSTANT),
+        \\"payload\\": Symbol(SOME_CONSTANT),
+        \\"type\\": \\"an-action\\",
       } 
       (See https://redux.js.org/faq/actions#why-should-type-be-a-string-or-at-least-serializable-why-should-my-action-types-be-constants) 
       (To allow non-serializable values see: https://redux-toolkit.js.org/usage/usage-guide#working-with-non-serializable-data)"