Reactive State Tree

A partially global state management that doesn't require optimisation.

Motivation

State management is hard, especially if a state effects multiple components which are in seperate branch of the component tree. Using Context Api in this scenario requires lots of optimisations with useRef, useCallback etc. and of course their deps needs to be managed. This library provides as clean as possible api without dealing with this overhead.

How to use

Installation

npm install reactive-state-tree

or

yarn add reactive-state-tree

Usage

Create a state tree

// state.js
import { createReactiveContext } from 'reactive-state-tree';

// The api returns tuple instead of object to make it easy to rename
const [Context, Provider, useRootState, useSelector] = createReactiveContext({
  count: 1,
  query: '',
});

export { Context, Provider, useRootState, useSelector };

Place the provider in component tree.

// App.js
import React from 'react';
import { Counter, Input, Root } from './components';

const App = () => {
  <Provider>
    <Root />
    <Counter />
    <Input />
  </Provider>;
};

Access the state via hooks exposed by the state

// components.js
import React from 'react';
import { useSelector, useRoot } from './state';

export const Counter = () => {
  const [count, setCount] = useSelector('count');

  const handleIncrement = () => setCount(count => count + 1);
  const handleDecrement = () => setCount(count => count - 1);

  return (
    <div>
      <label>Count: {count}</label>
      <button onClick={handleIncrement}>Inc</button>
      <button onClick={handleDecrement}>Dec</button>
    </div>
  );
};

export const Input = () => {
  const [query, setQuery] = useSelector('query');

  const handleUpdate = e => setQuery(e.target.value);

  return (
    <div>
      <label>Query: {count}</label>
      <input onChange={handleUpdate} value={query} />
    </div>
  );
};

export const Root = () => {
  const [rootState, setRootStae] = useRoot();

  const initialState = React.useRef(rootState);

  const handleReset = () => setRootState(initialState.current);

  return (
    <div>
      <pre>{JSON.stringify(rootState)}</pre>
      <button onClick={handleReset}>Reset</button>
    </div>
  );
};

So what is the catch? Same thing can be achieved by using useState hook. Not really, this example shows the most basic usa case. Please check the examples below.

Examples

• Shopping Cart

More examples are coming...

API Reference

Api	Params	Description
Provider	initialState	Provider
Context	none	Context
useRoot	none	Hook returns a tuple with root state and root state updater like React.useState
useSelector	key: string (key of the given state), condition: callback function takes state and returns boolean, based on returned boolean the state will be updated or not	Hook returns a tuple with root state and root state updater like React.useState

Planned Features

• Compostion api which will provide create another state tree by using other state trees.
• Dev tool, will help to track changes and exlore states.
• map api, will allow to use mapped value directly from the state

Contribution

This project 100% open to any kind of contribution.