Actually throw an error when there's no initialState

Author: markerikson

packages/toolkit/src/createSlice.ts

@@ -268,7 +268,7 @@ export function createSlice<
     process.env.NODE_ENV === 'development'
   ) {
     if(options.initialState === undefined) {
-      console.error('initial state must be different of undefined')
+      throw new Error('You must provide an `initialState` value that is not `undefined`.  You may have misspelled `initialState`')
     }
   }
 

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

@@ -13,7 +13,7 @@ describe('createSlice', () => {
     restore = mockConsole(createConsole())
   })
 
-  describe('when slice is undefined', () => {
+  describe('when name is undefined', () => {
     it('should throw an error', () => {
       expect(() =>
         // @ts-ignore
@@ -29,7 +29,7 @@ describe('createSlice', () => {
     })
   })
 
-  describe('when slice is an empty string', () => {
+  describe('when name is an empty string', () => {
     it('should throw an error', () => {
       expect(() =>
         createSlice({
@@ -47,17 +47,17 @@ describe('createSlice', () => {
 
   describe('when initial state is undefined', () => {
     it('should throw an error', () => {
-      createSlice({
-        name: 'test',
-        reducers: {},
-        initialState: undefined,
-      })
-
-      expect(getLog().log).toBe('initial state must be different of undefined')
+      expect(() =>
+        // @ts-ignore
+        createSlice({
+          name: 'test',
+          reducers: {},
+        })
+      ).toThrowError('You must provide an `initialState` value that is not `undefined`.  You may have misspelled `initialState`')
     })
   })
 
-  describe('when passing slice', () => {
+  describe('when passing name', () => {
     const { actions, reducer, caseReducers } = createSlice({
       reducers: {
         increment: (state) => state + 1,