Redux scheme for `normalizr.js` and TypeScript

actions.ts

import { TOAST_NOTIFICATION_TRIGGERED } from '../../../constants/ActionTypes'
import { NotificationKind, ToastNotification } from './types'
import { normalizeToastNotification } from './schema'

export interface Action {
  type: TOAST_NOTIFICATION_TRIGGERED
  entities: object
  id: ToastNotification['notificationId']
}

export const triggerToastNotification = (
  kind: NotificationKind,
  message: string,
  timeoutLength: number = 3000
): Action => ({
  type: TOAST_NOTIFICATION_TRIGGERED,
  ...normalizeToastNotification({
    notificationId: String(Date.now()),
    kind,
    message,
    timeoutLength,
  })
})

entities-reducer.ts

import { normalizeToastNotification } from './schemas'

export const entitiesReducer = (state: object = {}, action: RootAction) => {
  switch (action.type) {
    case TOAST_NOTIFICATION_TRIGGERED:
      return {
         ...state,
         ...action.entities,
      }
  default:
    return state
}

schema.ts

import { schema, normalize } from 'normalizr'
import { ToastNotification } from './types'

// Would have a generic helper to define these
export interface NormalizeToastNotificationResult {
  entities: object
  result: ToastNotification['notificationId']
}

const toastNotificationSchema = new schema.Entity('toastNotifications', {
  idAttribute: 'notificationId',
})

export const normalizeToastNotification = (
  toastNotification: ToastNotification
) =>
  normalize(
    toastNotification,
    toastNotificationSchema
  ) as NormalizeToastNotificationResult

export const denormalizeToastNotification = (
  id: ToastNotification['notificationId'],
  entities: object
) =>
  denormalize(
    id,
    toastNotificationSchema,
    entities
  ) as ToastNotification

selectors.ts

import { denormalizeToastNotification } from './schemas'

export const selectToastNotifications = state =>
  state.toastNotifications.map(id => denormalizeToastNotification(id, state.entities))

toast-notifications-reducer.ts

type ToastNotificationId = ToastNotification['notificationId']

export const toastNotificationsReducer = (
  state: ToastNotificationId[] = [],
  action: RootAction
) => {
  switch (action.type) {
    case TOAST_NOTIFICATION_TRIGGERED:
      return [...state, action.id]
    default:
      return state
  }
}