Help with Expense Tracker project (step 8)

I need help with the Expense Tracker project.
I did all the steps, and when I got to the last one, where we are asked to write the transactionsSlice with createSlice function, I ran the code, nothing rendered and when looking at the console this is what I got:

Uncaught ReferenceError: transactionsReducer is not defined
    at [email protected]/toolkit (index.compiled.js:712:16)
    at o (index.compiled.js:1:265)
    at index.compiled.js:1:316
    at 14.../../components/TransactionForm (index.compiled.js:621:26)
    at o (index.compiled.js:1:265)
    at index.compiled.js:1:316
    at 6.../features/budgets/Budgets (index.compiled.js:225:44)
    at o (index.compiled.js:1:265)
    at index.compiled.js:1:316
    at 16../app/App (index.compiled.js:722:35)

I found that in the index.compiled.js on line 722, there is indeed a call to transactionReducer, which I removed since writing the reducer inside the createSlice method, and it seems to come from this line in the transactionsSlice file:
export const selectFlattenedTransactions = (state) => Object.values(state.transactions).reduce((a,b) => […a, …b], );

Anybody has a clue what is going on?

By the way, this is my code inside transactionSlice.js, if this helps…

const transactionsSlice = createSlice({
  name: 'transactions',
  initialState: initialState,
  reducers: {
    addTransaction: (state, action) => {
    deleteTransaction: (state,action) => {
      state[action.payload.category].filter(obj => !==;

export const selectTransactions = (state) => state.transactions;
export const selectFlattenedTransactions = (state) => Object.values(state.transactions).reduce((a,b) => [...a, ...b], []);

export {addTransaction, deleteTransaction} = transactionsSlice.actions;
export default transactionsSlice.reducer;