Pragmatic and concise state management.

• single store modified via actions
• tiny api - easy to understand, easy to adapt
• tiny size - 1KB, or 2KB with (p)react bindings
• react and preact bindings included
• react hooks support
• highly optimised with batched rerenders
• beautiful console logger
• redux devtools integration

How is this different from redux? The key differences are:

• Actions in tiny-atom are self contained units of business logic. They can read and update the state and dispatch other actions any number of times. This removes layers of boilerplate while preserving the benefits of redux like stores.
• Tiny-atom includes useful utilities to make it completely sufficient for building application of any size.

Installation

$ npm install tiny-atom

Docs

Read the full docs or pick one of the highlights:

• Basics
• Prior art
• Using with React
• Using with Preact
• API Reference

Example

import createAtom from 'tiny-atom'

const atom = createAtom({ unicorns: 0, rainbows: [] }, {
  incrementUnicorns ({ get, set }, n) {
    set({ unicorns: get().unicorns + n })
  },

  async fetchRainbows ({ set, actions }) {
    set({ loading: true })
    const { data: rainbows } = await axios.get('/api/rainbows')
    set({ rainbows, loading: false })
    actions.incrementUnicorns(1)
  }
})

atom.observe(atom => {
  console.log('atom', atom)
  const { rainbows, unicorns } = atom.get()
  render(unicorns).onClick(e => atom.actions.incrementUnicorns(10))
})

React Example

Provide the store:

import React from 'react'
import ReactDOM from 'react-dom'
import createAtom from 'tiny-atom'
import { Provider } from 'tiny-atom/react'

const atom = createAtom({ user: { name: 'Atom' } }, {
  message ({ get, set, swap, actions }, msg) {
    console.log(msg)
  }
})

ReactDOM.render((
  <Provider atom={atom}>
    <App />
  </Provider>
), document.querySelector('root'))

Connect using React hooks:

import React from 'react'
import { useAtom, useActions } from 'tiny-atom/react/hooks'

export default function Hello () {
  const user = useAtom(state => state.user)
  const { message } = useActions()

  return (
    <button onClick={() => message('hi')}>{user.name}</button>
  )
}

API

createAtom(initialState, actions, options)

Create an atom.

initialState

type: any default: {}

The initial state of the atom.

actions

type: object default: {}

An object with action functions. The signature of an action function is ({ get, set, swap, actions, dispatch }, payload). If you provide nested action objects or other structure, make sure to also specify an appropriate options.evolve implementation to handle your actions appropriately.

• get() - returns the current state
• set(patch) - updates the state with the patch object by merging the patch using Object.assign
• swap(state) - replace the entire state with the provided one
• dispatch - same as atom.dispatch, dispatches an action
• actions - actions prebound to dispatch, i.e. actions.increment(1) is equivalent to dispatch('increment', 1)

options.evolve

type: function

A function that receives all of the dispatched action objects and calls the action functions. The function signature is (atom, action, actions). Note that atom in this place has an extra added function set, a function that is used to update the state, this function does not exist on the actual atom. The default implementation uses action.type to find the matching function in the actions object.

options.debug

type: function | function[] default: null

A function that will be called on each action and state update. The function is passed an info object of shape { type, atom, action, sourceActions, prevState }. Tiny atom comes with 2 built in debug functions tiny-atom/log and tiny-atom/devtools.

createAtom({ count: 1 }, {
  increment: ({ get, set }, payload) => set({ count: get().count + payload }),
  inc: ({ actions }, payload) => actions.increment(payload)
})

atom.get()

Get current state.

atom.get()
atom.get().feed.items

atom.set(update)

Update state by shallowly merging an update.

atom.set({ user })
atom.set({ entities: { ...get().entities, posts } })

atom.swap(state)

Replace the entire state with the provided one.

atom.swap(nextState)

atom.dispatch(type, payload)

Send an action

atom.dispatch('fetchMovies')
atom.dispatch('increment', 5)

atom.actions

A map of prebound actions. For example, if your actions passed to atom are

const actions = {
  increment ({ get, set }) {
    const { count } = get()
    set({ count: count + 1 })
  }
}

They will be bound such that calling atom.actions.increment(1) dispatches action with `dispatch('increment', 1).

atom.observe(cb)

Register a callback for when atom changes. Returns the unobserve function.

atom.observe(render)
atom.observe(atom => render(atom.get(), atom.dispatch))

atom.fuse(state, actions)

Extend atom's state and the action object. Convenient for composing atom from slices of state and actions from several modules.

const state = {
  project: { name: 'tiny-atom' }
}

const actions = {
  star: ({ get, set }) => set({
    project: { starred: true }
  })
}

atom.fuse(state, actions)

React / Preact bindings

For documentation on the set of react and preact components <Provider />, <Consumer />, connect, useAtom, useActions and useDispatch see react or preact docs.