mutik

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A tiny (495B) immutable state management library based on Immer

Quick Start

yarn add mutik

or

Table of Contents

• Example
• API
  • createStore<S>(intialState: S): Store<S>
    • store
  • useSelector<S, V>(selector: (s: S) => V)
  • <Provider />
• Author
• Inspiration

Example

To use Mutik with React, you'll need to install React and React DOM from the experimental release channel because Mutik uses the recently-merged useMutableSource hook internally.

yarn add react@experimental react-dom@experimental

import React from 'react';
import { render } from 'react-dom';
import { createStore, Provider, useSelector } from 'mutik';

// Create a lil' store with some state
let store = createStore({
  count: 0,
});

// Pass the store to the Provider.
function App() {
  return (
    <Provider store={store}>
      <div>
        <Label />
        <Buttons />
      </div>
    </Provider>
  );
}

// You can mutate the store from anywhere you want to,
// even outside of React code. Mutate is based on immer.
function increment() {
  store.mutate(state => {
    state.count++;
  });
}

// Or you can update it like React.useState's update
function decrement() {
  store.set(prevState => ({
    ...prevState,
    count: prevState.count - 1
  });
}

// You don't need to pass the store down as a prop either
function Buttons() {
  return (
    <React.Fragment>
      <button onClick={decrement}>-</button>
      <button onClick={increment}>+</button>
    </React.Fragment>
  );
}

// Lastly, you can subcribe to "slices" of state with useSelector
// Note: be sure to memoize these with React.useCallback if you need to select based on props
function Label() {
  const selector = React.useCallback(state => state.count, []);
  const count = useSelector(selector);
  return <p>The count is {count}</p>;
}

render(<App />, window.root);

API

createStore<S>(intialState: S): Store<S>

Create a Mutik store given some initial state. The store has the following API you can use in or out of React.

store

useSelector<S, V>(selector: (s: S) => V)

React hook to subscribe to Mutik state. Must be called underneath a Mutik Provider.

const selector = state => state.count;

function Label() {
  const count = useSelector(selector);
  return <p>The count is {count}</p>;
}

You can use props with Mutik selector. For performance, it's a good idea to memoize the selector with React.useCallback. For example:

function User({ id }) {
  const selector = React.useCallback(state => state.users[id], [id]);
  const user = useSelector(selector);
  return <p>The username is {user.name}</p>;
}

<Provider />

Mutik context provider. Pass your store as store prop. For example:

import React from 'react';
import { createStore, Provider } from 'mutik';

// Create a lil' store with some state
let store = createStore({
  count: 0,
});

// Pass the store to the Provider.
function App() {
  return (
    <Provider store={store}>
      <div>{/* ... stuff */}</div>
    </Provider>
  );
}

Author

• Jared Palmer @jaredpalmer

Inspiration

• bey
• react-copy-write
• Brian Vaughn's fake redux

MIT License