@featherweight/actions-reducer
v0.4.1
Published
Minimalistic typesafe actions and reducers
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Featherweight actions reducer
Setup
npm install --save @featherweight/actions-reducer
Usage
import {createAction, createReducer} from '@featherweight/actions-reducer'
/* Define your actions */
const increment = createAction('counter: increment')
const add = createAction<number>('counter: add')
/* Create reducer */
const initialCounter = 0
const reducer = createReducer(
on => [
on(increment, state => state + 1),
on(add, ((state, action) = state + action.payload)),
],
initialCounter,
)
/* All set, you can use reducer */
const reduxStore = createStore(reducer)
/* Also you can define your handlers outside of reducer using HandlerOf type */
const decrement = createAction('counter: decrement')
const decrementHandler: HandlerOf<
typeof initialState,
typeof decrement
> = state => state - 1
/* And you can attach handlers to your reducer dynamically */
reducer.on(decrement, decrementHandler)
/* It supports meta and error fields as well */
const allInOne = createAction<string | Error, {flag: boolean}>('all in one')
allInOne(new Error('nope'), {flag: true})
API
action
Flux Standard Action compatible action.
<P, M>(type: ActionType, payload: P, meta: M) => FSA<P, M>
import {action} from '@featherweight/actions-reducer'
action('plain action')
// {type: 'plain action'}
action('with payload', {ping: 'pong'})
// {type: 'with payload', payload: {ping: 'pong'}}
action('with meta', 42, {hi: 'there'})
// {type: 'with payload', payload: 42, meta: {hi: 'there'}}
createAction
Action creator factory.
<P, M>(type: ActionType) => (payload?: P, meta?: M) => FSA<P, M>
import {createAction} from '@featherweight/actions-reducer'
const ping = createAction('ping')
ping()
// {type: 'ping'}
const setValue = createAction<number>('set value')
setValue(300)
// {type: 'set value', payload: 300}
const fetchUser = createAction<string, {ts: Date}>('fetch user')
fetchUser('user-id', {ts: new Date()})
// {type: 'fetch user', payload: 'user-id', meta: {ts: Date}}
createReducer
Reducer creator with type inference.
<S>(createHandlers: (on: Handler<S>) => HandlerTuple<S>[], initialState?: S) => Reducer
import {createAction, createReducer} from '@featherweight/actions-reducer'
const actions = {
ping: createAction('ping'),
setValue: createAction<number>('set value'),
}
const initialState = {pinged: false, value: 0}
const reducer = createReducer(
on => [
on(actions.ping, (state, action) => {
return {...state, pinged: true}
}),
on(actions.setValue, (state, action) => {
return {...state, value: action.payload}
}),
],
initialState,
)
// you can omit initialState if you want to provide it later
// like using React.useReducer hook: useReducer(reducer, initialState)
// but you might want to provide State as a type parameter to have type checking
type State = {pinged: boolean}
const reducer = createReducer<State>(on => [
on(actions.ping, (state, action) => ({...state, pinged: true})),
/* ... */
])
createReducerWithState
The same as createReducer
but you can only attach handlers dynamically.
<S>(initialState?: S) => Reducer & {on: Handler<S>}
import {
createAction,
createReducerWithState,
} from '@featherweight/actions-reducer'
const initialState = {pinged: false, value: 0}
const reducer = createReducerWithState(initialState)
const ping = createAction('ping')
reducer.on(ping, (state, action) => ({...state, pinged: true}))
const setValue = createAction<number>('set value')
reducer.on(setValue, (state, action) => ({...state, value: action.payload}))
// you can use createReducerWithState without providing initialState
// (the same way as createReducer)
type State = {pinged: boolean}
const reducer = createReducerWithState<State>()
helpful types
This package also includes some types, that might be useful in some situations.
HandlerOf
type is useful when you want to define your handler outside of reducer
import {
createAction,
createReducer,
HandlerOf,
} from '@featherweight/actions-reducer'
type State = {count: number}
const add = createAction<number>('add')
const addHandler: HandlerOf<State, typeof add> = (state, action) => {
return {...state, count: state.count + action.payload}
}
// you can use it later in reducer
const reducer = createReducer(on => [on(add, addHandler)], {count: 0})
ActionOf
type is useful when you want to use your action creator return type
import {ActionOf, createAction} from '@featherweight/actions-reducer'
import {takeLatest} from 'redux-saga/effects'
type FetchUserPayload = {id: string; search: Record<string, string>}
const fetchUser = createAction<FetchUserPayload>('fetch user')
function* rootSaga() {
yield takeLatest(fetchUser, fetchUserSaga)
}
function* fetchUserSaga(action: ActionOf<typeof fetchUser>) {
action.payload.id // string
action.paylaod.search // Record<string, string>
/* ... */
}