import { v4 } from "react-native-uuid"; export default function timetable(state, action) { if (typeof state === "undefined") // Array of days starting with Sunday return [ [], [], [], [], [], [], [], ]; switch (action.type) { case "ADD_TIMETABLE_ENTRY": return [ ...(state.slice(0, action.day)), [...state[action.day], { ...action.entry, id: v4() }], ...(state.slice(action.day + 1)) ]; default: return state; } }