Retomic

Retomic is a reactive state management system for React. The idea for this library is based on the idea of clojure's atoms.

Installation

The Retomic package lives in npm. To install the latest stable version, run the following command:

npm install retomic

Usage

RetomicRoot

Retomic includes a RetomicRoot component which creates a single object tree for the application state.

import React from 'react'
import ReactDOM from 'react-dom'
import App from './App'

const rootElement = document.getElementById('root')
ReactDOM.render(
  <RetomicRoot>
    <App />
  </RetomicRoot>,
  rootElement
)

Atoms

Retomic atoms are slices of your state accessed based on their key property.

import { atom } from 'retomic'

export const counterAtom = atom({
  key: 'counter',
  defaultState: 0
})

Hooks

Retomic provides a pair of hooks for reading and writing data to your atoms.

useRead reads a value from an atom and watches for updates while useSend returns a send function to send updates via update functions.

import { useRead, useSend } from 'retomic'
import { counterAtom } from './counter-atom'

const increment = (state, x) => state + x
const decrement = (state, x) => state - x

function Counter() {
  const count = useRead(counterAtom, d => d)
  const send = useSend(counterAtom)

  return (
    <div>
      <button
        aria-label="Increment value"
        onClick={() => send(increment, 1)}
      >
        +
      </button>
      <span className={styles.value}>{count}</span>
      <button
        aria-label="Decrement value"
        onClick={() => send(decrement, 1)}
      >
        -
      </button>
    </div>
  )
}

API

atom

type atom({
  key,
  defaultState,
  resetOnInactive
}: {
  key: string,
  defaultState: any,
  resetOnInactive?: boolean
})

useRead

useRead<T>(
  atom: Atom<T>,
  selector: SelectorFn<T, SelectorValue>,
  isEqualFn: IsEqualFn<SelectorValue> = shallowEqual
)

useSend

useSend<T>(atom: Atom<T>):
  <Payload>(
    updateFn: UpdateFn<T, Payload>,
    payload: Payload
  ): void