In the upcoming lecture, we will be working on adding our CellList component. You may see the following TS error:

Property 'order' does not exist on type 'CellsState | undefined'.

Property 'data' does not exist on type 'CellsState | undefined'.

As raised in the QA here, you will need to add initialState as a second argument to the produce function of cellsReducer.ts:

const reducer = produce((state: CellsState = initialState, action: Action) => {
    ...
  }
}, initialState);