redux-easy-mode

A very easy to understand and use set of tools for Redux. Includes:

• Easy way of defining actions
• Easy way of building reducers
• Async / Promise based actions
• Action-based side effects
• Selector-based side effects
• TypeScript support

Actions and Reducers

Actions

Actions are built using a namespace and an object of "payload creators". The property names are considered the action types.

A payload creator is a function that takes any number of arguments and returns what will be the action's payload (or, if you'd prefer, you can return both a payload and meta.)

import { createActions } from 'redux-easy-mode'

export default createActions('example', {
  // A simple action with no arguments or payload
  increment: () => undefined,

  // An action with an argument that also returns a payload.
  setIncrementBy: (n: number) => n,
  // Which could also be written as this.
  // setIncrementBy: identityPayloadCreator<number>(),

  // An action that returns meta, payload, and even overrides the action type.
  // Note that when you override the action type, the `.actionType` property
  // will be inconsistent.
  safeSetIncrementBy: (n: number) => ({
    type: 'example/setIncrementBy',
    payload: n > 10 ? 10 : n,
    meta: {
      wasTooLarge: n > 10,
    },
  }),

  // An async action. See below for notes on the async middleware.
  asyncAction: () => async (dispatch, getState) => ({
    foo: 42,
  }),
})

Reducers

createReducer builds a reducer for you. No more switch statements.

It uses a builder pattern, so return types are inferred for you.

import { createReducer } from 'redux-easy-mode'

import actions from './actions'

const initialState = {
  currentNumber: 0,
  incrementBy: 1,
}

export default createReducer(initialState, (builder) => {
  builder
    // Passing an action creator will automatically infer type of the action.
    .addHandler(actions.increment, (state, action) => ({
      ...state,
      currentNumber: state.currentNumber + state.incrementBy,
    }))

    // You can still go the string route if you need to.
    // Note that when you do this, the type of the action cannot be inferred for
    // you.
    .addHandler(
      'example/setIncrementBy',
      (state, action: ReturnType<typeof actions.setIncrementBy>) => ({
        ...state,
        incrementBy: action.payload,
      }),
    )

    // There's also methods to infer the async result for you.
    .addSuccessHandler(actions.asyncAction, (state, action) => ({
      ...state,
      currentNumber: action.payload.foo,
    }))
})

---

Async Middleware

Allows you use async functions for payloads in redux. Also supports Promises and synchronous code. Gives thunk abilities when payload is a function.

Example

store.dispatch({
  type: 'fetchResults',
  payload: async (dispatch, getState) => {
    const results = await someApiCall()

    dispatch({
      type: 'recordResults',
      payload: results,
    })
  },
})

This will dispatch 3 actions, in this order:

[
  {
    "type": "fetchResults/start"
  },
  {
    "type": "recordResults",
    "payload": ["results of your api call"]
  },
  {
    "type": "fetchResults/success"
  }
]

Installation

import { applyMiddleware, createStore } from 'redux'
import { asyncMiddleware } from 'redux-easy-mode'

const configureStore = applyMiddleware(asyncMiddleware())(createStore)

Awaiting dispatch

When calling dispatch() with an async function, it will return Promise<any>. That means that you can await it when dispatching your actions throughout your code, enabling more ways of combining async actions.

Skip /start and /success actions

These actions are dispatched by the middleware when the payload is either a Function or a Promise. You can skip them by adding metadata to your action. This acts more like redux-thunk without having to install both middleware:

store.dispatch({
  type: 'foo',
  payload(dispatch) {
    dispatch(/* */)
  },
  meta: {
    asyncPayload: {
      skipOuter: true,
    },
  },
})

Handle payload as Promise instead of async function.

The payload can be a Promise. This will also dispatch the /start and /success actions:

dispatch({
  type: 'fetchResults',
  payload: someApiCall(),
})

Passing data to /success action

No matter what you initially pass as a payload, the /success action will receive the result of it should you want to do anything with it in a reducer or at the point of dispatching:

dispatch({ payload: Promise.resolve(42), type: 'fetchResults' })
// { payload: 42, type: 'fetchResults/success }

dispatch({
  async payload() {
    return 42
  },
  type: 'fetchResults',
})
// { payload: 42, type: 'fetchResults/success }

dispatch({
  payload() {
    return 42
  },
  type: 'fetchResults',
})
// { payload: 42, type: 'fetchResults/success }

Types for reducers

redux-async-payload comes with ActionStartType, ActionSuccessType, and ActionErrorType.

Using the actions and reducer helpers greatly simplifies this.

function reducer(state = initialState, action: AnyAction) {
  switch (action.type) {
    case startActionType(actions.constants.myAction): {
      action = action as ActionStartType<typeof actions.myAction>

      return {
        ...state,
      }
    }

    case successActionType(actions.constants.myAction): {
      action = action as ActionSuccessType<typeof actions.myAction>
      return {
        ...state,
      }
    }

    case errorActionType(actions.constants.myAction):
      {
        action = action as ActionErrorType<typeof actions.myAction>
        return {
          ...state,
        }
      }

      return state
  }
}

---

Side Effects

If async actions are not enough for you, there is also a side effect middleware. These allow you to run functions when actions are dispatched, or when some part of the state changes based on a selector.

Installation

import { applyMiddleware, createStore } from 'redux'
import { sideEffectMiddleware } from 'redux-easy-mode'

const configureStore = applyMiddleware(sideEffectMiddleware())(createStore)

Action-based side effects

These side effects will be called whenever given action is dispatched. You are given access to the store, and can optionally return a function to do some cleanup.

import { reduxActionSideEffect } from 'redux-easy-mode'

reduxActionSideEffect(actions.increment, (action, dispatch, getState) => {
  console.log(`${actions.increment.actionType} was dispatched`)

  // Return a function if you'd like to do some cleanup before this function is
  // called again.
  return () => {
    console.log('cleanup')
  }
})

Selector-based side effects

These side effects are run whenever the resulting value of your selector has changed. You are given access to the store, and can optionally return a function to do some cleanup.

import { reduxSelectorSideEffect } from 'redux-easy-mode'

reduxSelectorSideEffect(
  (state: RootState) => state.some.value,
  (value, previousValue, dispatch, getState) => {
    console.log('value:', value)
    console.log('previousValue:', previousValue)

    // Return a function if you'd like to do some cleanup before this function
    // is called again.
    return () => {
      console.log('cleanup')
    }
  },
)

---

See Also

• Redux Toolkit. Includes utilities to simplify common use cases like store setup, creating reducers, immutable update logic, and more.
• redux-ts-helpers and redux-async-payload. These were two redux tools I built in 2017. redux-easy-mode is these two mashed together, inspired by Redux Toolkit.