Reduce boilerplate code by automatically creating action creators and action types from reducers.
npm install redux-reflexReduce boilerplate code by automatically creating action creators and action types from reducers.
 
- Installation
- Example
- Documentation
- Reducer
- Actions
- Async Actions
- Reusing Reducer Logic
- License
``bash`
npm install redux-reflex --save
reducer.js
`js
import Reducer from 'redux-reflex'
const prefix = 'counter'
const initialState = { count: 0 }
const handlers = {
// called when action type is 'counter/increment'
increment(state, amount) {
return { ...state, count: state.count + amount }
},
// called when action type is 'counter/decrement'
decrement(state, amount) {
return { ...state, count: state.count - amount }
},
}
const counter = Reducer(prefix, initialState, handlers)
export default counter
`
This will create a reducer function counter with initialState as the initial state and handlers as case reducers. handlers handle actions with type starting with prefix.
You don't have to define action creators or action types. They are automatically created and attached to the reducer function:
`js
counter.increment // action creator (function)
counter.increment.type // action type (string) - 'counter/increment'
counter.increment() // creates action (object) - { type: 'counter/increment' }
dispatch(counter.increment(5)) // increases count by 5
`
Generated actions are similar to [Flux Standard Action].
`js
counter.increment()
/*
{
type: 'counter/increment',
}
*/
counter.increment(5)
/*
{
type: 'counter/increment',
payload: 5,
}
*/
`
If payload is an instance of an [Error][Error] object then error is automatically set to true.
`js`
counter.increment(new Error())
/*
{
type: 'counter/increment',
payload: new Error(),
error: true,
}
*/
The main Reducer function creates a reducer and corresponding action creators and types.
`js
import Reducer from 'redux-reflex'
const todos = Reducer(...)
`
#### Reducer(prefix, initialState, handlers, options = {})
##### prefix
prefix should be unique as prefix + '/' is used as a prefix for the action types that are automatically created. You can follow this convention to keep them unique: .
##### initialState
Initial value of the state managed by reducer.
##### handlers
Action handlers let you split the reducer code into smaller functions instead of using switch-case statements. These are also called "case reducers".
###### handler(state, payload, action)
Each handler should be a pure function that reads current state, payload and action and returns a new state: (state, payload, action) => state. A typical reducer function looks like (state, action) => state but here payload is passed as the second argument as it will be required most of the time. If you need more info about an action, you can always use the third argument action which contains action type, payload and other data related to action. For example, to check if an action is dispatched because of an error:
`js
// some action handler
fetched(state, payload, { error }) {
// state should not be modified directly
// so do a shallow copy first
state = { ...state }
// state updates common to both success and failure cases
state.fetching = false
// failure case
if (error) {
state.error = payload
return state
}
// success case
state.data = payload
return state
}
`
Here we used [Destructuring assignment] to unpack error from the third argument action.
##### options
options object is used for configuring the Reducer. Currently these options are available:
`jstrue
{
copy: false,
// when , Reducer automatically does a shallow copy of state
// before calling a handler function
}
`js
import Reducer from 'redux-reflex'
const todos = Reducer(
'todos',
{ todos: [] },
{
// this function will be called when action type is 'todos/add'
add(state, { text }) {
// Since copy option is set to true, Reducer automaticallystate
// does a shallow copy of before calling this function.{ ...state }
// So you don't have to do .
// concat() returns a new copy of arraypush()
// and doesn't modify the original one.
// should not be used as it modifies
// the original array.
state.todos = state.todos.concat(text)
return state
},
},
{ copy: true }
)
`
Here we used [Destructuring assignment] to unpack text from payload. If payload is not passed as second argument then unpacking complex objects becomes hard to read.
Action creators are automatically created from reducer functions. If you need to define more action creators, you can use the Action function:
`js
import { Action } from 'redux-reflex'
todos.add = Action('todos/add')
todos.add({ text: 'some task' })
/*
{
type: 'todos/add',
payload: { text: 'some task' },
}
*/
`
#### Action(type, transform = payload => payload)
##### type
type specifies the action type and should be unique. You can follow this convention to keep it unique: .
##### transform
transform is a function that can be used to modify the payload:
`js
import { Action } from 'redux-reflex'
todos.add = Action('todos/add', payload => ({ text: payload }))
todos.add('some task')
/*
{
type: 'todos/add',
payload: { text: 'some task' },
}
*/
`
#### transform(actionCreator, transform)
Apply a transform function to existing action creators:
`js
import Reducer, { transform } from 'redux-reflex'
const todos = Reducer(...) // assume that todos.add is already defined here
todos.add('some task')
/*
{
type: 'todos/add',
payload: 'some task',
}
*/
todos.add = transform(todos.add, payload => ({ text: payload }))
todos.add('some task')
/*
{
type: 'todos/add',
payload: { text: 'some task' },
}
*/
`
Async actions can be handled using a middleware like [redux-thunk][redux-thunk]:
`jstodos.fetching
// define and todos.fetched using Reducer functionerror
// and use the property inside todos.fetched handler function
// to handle both success and failure cases
todos.fetch = () => dispatch => {
dispatch(todos.fetching())
return api
.get('/todos')
.then(response => dispatch(todos.fetched(response.data)))
.catch(error => dispatch(todos.fetched(error)))
}
// dispatch it like a normal action
dispatch(todos.fetch())
`
Let's say you want to have two counters both having their own state but with same functionality. To do so, you just have to define two reducers with same initial state and handlers:
`js
import { combineReducers, createStore } from 'redux'
import Reducer from 'redux-reflex'
const initialState = { count: 0 }
const handlers = {
increment(state, amount) {
return { ...state, count: state.count + amount }
},
decrement(state, amount) {
return { ...state, count: state.count - amount }
},
}
const counter1 = Reducer('counter1', initialState, handlers)
const counter2 = Reducer('counter2', initialState, handlers)
const store = createStore(combineReducers({ counter1, counter2 }))
`
Here counter1 and counter2 have their own slice of state and calling an action of one counter doesn't affect the state of other.
`js
counter1.increment() // handled by counter1 reducer
/*
{
type: 'counter1/increment',
}
*/
counter2.increment() // handled by counter2 reducer
/*
{
type: 'counter2/increment',
}
*/
``
[MIT][license]
[license]: /LICENSE
[Flux Standard Action]: https://github.com/acdlite/flux-standard-action
[redux-thunk]: https://github.com/gaearon/redux-thunk
[Error]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error
[Destructuring assignment]: https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Operators/Destructuring_assignment