smitty

Tiny flux implementation built on mitt

smitty

• Install
• Basic Usage
• Demos
• Usage with Preact and React
• API
• Store
• Action Creator Detailed Example
• Class As Reducer

Install

npm install -S smitty

Basic Usage

import { createStore } from 'smitty'

// Create a store with initial state
const initialState = { count: 0 }
const store = createStore(initialState)

store.createActions({
  add: 'count/ADD'
})

// add a reducer
store.handleActions({
  [store.actions.add]: (state, e, type) => {
    // increment foos by amount
    return Object.assign({}, state, { count: state.count + e.amount })
  },
  '*': (state, e, type) => {
    // '*' can be used for all kinds of fun stuff
    console.log(e, type)
    if (type === 'count/ADD') {
      //...do something
    }
    return state
  }
})

store.actions.add({ amount: 5 })

console.log(store.state)  // logs `{ count: 5 }`

---

Demos (v2)

• Photo Booth Demonstrates async api and saving parts of the store with localforage
  • source

Demos (v1)

• Basic
  • Object as state
  • Map as state
  • Immutable.Map as state
  • Preact Router Example
• Async
  • Fetch api with Immutable.Map as state
• Fun
  • UI colors with Immutable.Map as state
  • UI colors with custom class as state
  • Scroll sync
  • Preact Component as state

---

Usage with Preact and React

• Preact bindings - preact-smitty

  npm install preact-smitty

• React bindings - react-smitty

  npm install react-smitty

---

API

createStore(initialState: any)

Arguments

initialState: any required: Determines the shape and initial state of your store. Can be of any type that you choose.

Returns

Store: Store Store

---

Store

emit: (function)

arguments

type: (string | function)

• [string], type determines which reducers are called.

  const store = createStore(0)
  store.handleActions({
    add: function (state, payload) {
      return state + payload
    }
  })
  console.log(store.state) // logs 0
  store.emit('add', 1)
  console.log(store.state) // logs 1

• [function] type becomes an action creator that is passed 1 argument

  • store: Store

  This is useful to emit multiple actions from a single emit call.

  const store = createStore(0)
  store.handleActions({
    add: function (state, payload) {
      return state + payload
    }
  })
  function asyncAction (emit, state) {
    emit('add', 1)
    console.log(state) // logs 1
    setTimeout(() => {
      emit('add', 1)
      console.log(state) // logs 3
    }, 100)
    emit('add', 1)
    console.log(state) // logs 2
  }
      ```

payload: (any) optional

payload to pass to your reducer

const store = createStore({ name: 'Arrow' })
store.handleActions({
  'update/NAME': function (state, payload) {
    // I really don't care if you return a new state
    // Nobody is judging. Do what your ❤️ tells you.
    // Just be consistent
    return Object.assign({}, state, payload)
  }
})
console.log(store.state) // logs { name: 'Arrow' }
store.emit('update/NAME', { name: 'River' })
console.log(store.state) // logs { name: 'River' }

createActions(): (function)

arguments

actionMap: (object)

Object where key is the action creator's name and the value can be of type string or function.

If the value is a string, an action creator is attached to store.actions as a function that accepts one argument, payload.

store.createActions({
  add: 'count/ADD'
})

// The following are functionally equivalent
store.actions.add(1)

store.emit('count/ADD', 1)

Action creators with a string value can be used as the key in your actionMap in handleActions.

store.createActions({
  add: 'count/ADD'
})

// add a reducer
store.handleActions({
  [store.actions.add]: (state, e, type) => {
    // increment foos by amount
    return Object.assign({}, state, { count: state.count + e.amount })
  }
})

store.actions.add({ amount: 5 })

console.log(store.state)  // logs `{ count: 5 }`

If the value is a function, it must be a function that returns an action creator. For async action creators.

store.createActions({
  add: (amount) => {
    return (store) => {
      setTimeout(() => {
       store.emit('count/ADD', amount)
      }, 16)
    }
  }
})

store.actions.add(1)

handleActions(): (function)

arguments

handlerMap: (object)

Object with keys that correspond to action types passed to emit

When an event is emitted and the key matches the type the reducer is invoked with 3 arguments.

• state: (any) the store's state getter
• payload (any) the payload that was emitted
• type (string) the type that was emitted

const store = createStore({ color: 'blue', hovered: false })
store.handleActions({
  'merge': function (state, payload) {
    return Object.assign({}, state, payload)
  },
  'overwrite': function (state, payload) {
    return payload
  },

  // Could do the same in one
  // If you really miss redux do this and put a switch statement
  '*': function(state, payload, type) {
    return type === 'merge' ? Object.assign({}, state, payload) : payload
  }
})
console.log(store.state) // logs { color: 'blue', hovered: false }
store.emit('merge', { color: 'red' })
console.log(store.state) // { color: 'red', hovered: false }
store.emit('overwrite', { color: 'green', hovered: true, highlighted: false })
console.log(store.state) // { color: 'green', hovered: true, highlighted: false 

actions: (object)

Map of all the actions created in store.createActions

This is convenient so that you do not have to deal with action imports across your app.

on: (function)

Convenience shortcut for mitt.on.

off: (function)

Convenience shortcut for mitt.off.

---

Action Creator Detailed Example

You can pass a function to emit in order to create an action creator

running example

import { createStore } from 'smitty'

// Create a store with initial state
const initialState = {}
const store = createStore(initialState)

// add our reducer
store.handleActions({
  'api/GET_ROOM': (state, { id, res }) => {
    return {
      ...state,
      [id]: {
        ...state[id],
        ...res.data
      }
    }
  }
})

// create our action creators
const actions = {
  requestRoom (id) {
    return async (emit, state) => {
      emit('REQUEST_ROOM', { id, res: { data: { id } } })
      const res = await window.fetch(`https://api.mysite.com/${id}`)
      res.data = await res.json()
      emit('REQUEST_ROOM', { id, res })
    }
  }
}

// When calling emit with a function argument, the function will be called with `emit` and `state` as arguments
const result = store.emit(actions.requestRoom('1a'))

// Return whatever you like from your action creator
console.log(result) // logs "Promise {[[PromiseStatus]]: "pending", [[PromiseValue]]: undefined}"

// After the fetch call, `REQUEST_ROOM` is fired a second time with our response data
result.then(() => console.log(store.state)) // logs `{ 1a: { id: '1a', title: 'My Room' }``

Class As Reducer

Reducers are iterated with for (let type in reducer) {...} with no obj.hasOwnProperty check so this works.

const store = createStore({ foo: 5 })

class HistoryReducer {
  constructor (initialHistory = []) {
    this.history = createStore(initialHistory)
    this.history.handleActions({
      update: (state, e) => {
        state.push(e)
      }
    })
  }

  onUpdate (state, e, type) {
    this.history.emit('update', { state, e, type })
  }
}

HistoryReducer.prototype['foo/ADD'] = function (state, e, type) {
  state.foo += e.foo
  this.onUpdate(state, e, type)
}

const historyReducer = new HistoryReducer([])
store.handleActions(historyReducer)

store.emit('foo/ADD', { foo: 5 })
console.log(store.state.foo) // logs 10
store.emit('foo/ADD', { foo: 7 })
console.log(store.state.foo) // logs 17
console.log(historyReducer.history.state)
// logs
// [
//   { state: { foo: 10 }, e: { foo: 5 }, type: 'foo/ADD' },
//   { state: { foo: 17 }, e: { foo: 7 }, type: 'foo/ADD' }
// ]

Thanks

Thanks to developit for mitt and the project structure.