include value in message

Author: EskiMojo14

src/createStore.ts

@@ -284,9 +284,9 @@ export function createStore<
 
     if (typeof action.type !== 'string') {
       throw new Error(
-        `Action "type" property must be a string. Instead, the actual type was: ${kindOf(
+        `Action "type" property must be a string. Instead, the actual type was: '${kindOf(
           action.type
-        )}.`
+        )}'. Value was: '${action.type}' (stringified)`
       )
     }
 

test/createStore.spec.ts

@@ -575,16 +575,15 @@ describe('createStore', () => {
 
   it('throws if action type is not string', () => {
     const store = createStore(reducers.todos)
-    const expectedErr = /Action "type" property must be a string/
     expect(() =>
       store.dispatch({ type: false } as unknown as AnyAction)
-    ).toThrow(expectedErr)
+    ).toThrow(/the actual type was: 'boolean'.*Value was: 'false'/)
     expect(() => store.dispatch({ type: 0 } as unknown as AnyAction)).toThrow(
-      expectedErr
+      /the actual type was: 'number'.*Value was: '0'/
     )
     expect(() =>
       store.dispatch({ type: null } as unknown as AnyAction)
-    ).toThrow(expectedErr)
+    ).toThrow(/the actual type was: 'null'.*Value was: 'null'/)
 
     expect(() =>
       store.dispatch({ type: '' } as unknown as AnyAction)