Restate Library Documentation

@ryujaewan/restate is a lightweight library that simplifies state management in React applications. It enables easy sharing and updating of state across multiple components.

Table of Contents

• Restate Library Documentation
  • Table of Contents
  • Installation
  • Basic Usage
  • Advanced Features
    • Memoization
    • Update Options
  • API Reference
    • restate(initialState)
    • useUser()
    • useUser.get()
    • useUser.set(newState)
  • Examples
    • Multi-Component Updates
    • Using get() and set()

Installation

npm install @ryujaewan/restate

or

yarn add @ryujaewan/restate

Basic Usage

// state.ts
import { restate } from '@ryujaewan/restate';

export const useUser = restate({ id: 1, name: 'John Doe' });

// UserComponent.tsx
import React from 'react';
import { useUser } from './state';

function UserComponent() {
  const [user, setUser] = useUser();
  
  return (
    <div>
      <h1>User ID: {user.id}</h1>
      <p>Name: {user.name}</p>
      <button onClick={() => setUser({ ...user, id: user.id + 1 })}>
        Increment ID
      </button>
    </div>
  );
}

Advanced Features

Memoization

Restate allows you to optimize performance by memoizing state updates:

let [user, setUser] = useUser((prev, next) => {
  return prev.id % 2 === 0; // Component updates only when id is even
});

return (
  <h1 onClick={() => {
    setUser({
      id: Math.floor(Math.random() * 100),
    });
  }}>
    {user.id}
  </h1>
);

Update Options

You can control when updates occur using the updateOn option:

let [user, setUser] = useUser({ updateOn: 'topLevelChange' });

return (
  <h1 onClick={() => {
    setUser({
      id: Math.floor(Math.random() * 100),
    });
  }}>
    {user.id}
  </h1>
);

API Reference

restate(initialState)

Creates a new state hook.

• initialState: The initial state object.

Returns: A custom hook for managing state.

useUser()

Custom hook created by restate.

Returns: An array containing the current state and a setter function.

useUser.get()

Retrieves the current state without subscribing to updates.

useUser.set(newState)

Updates the state and triggers re-renders in subscribed components.

• newState: New state object or update function.

Examples

Multi-Component Updates

// ProfileComponent.tsx
import React from 'react';
import { useUser } from './state';

function ProfileComponent() {
  const [user] = useUser();
  return <p>Profile: {user.name}</p>;
}

// SettingsComponent.tsx
import React from 'react';
import { useUser } from './state';

function SettingsComponent() {
  const [user, setUser] = useUser();
  
  return (
    <button onClick={() => setUser({ ...user, name: 'Jane Doe' })}>
      Change Name
    </button>
  );
}

// App.tsx
import React from 'react';
import UserComponent from './UserComponent';
import ProfileComponent from './ProfileComponent';
import SettingsComponent from './SettingsComponent';

function App() {
  return (
    <div>
      <UserComponent />
      <ProfileComponent />
      <SettingsComponent />
    </div>
  );
}

In this example, when the name is changed in SettingsComponent, both UserComponent and ProfileComponent will automatically update to reflect the new name.

Using get() and set()

// NonReactiveComponent.tsx
import React from 'react';
import { useUser } from './state';

function NonReactiveComponent() {
  const handleClick = () => {
    const currentUser = useUser.get();  // This component won't re-render on state changes
    console.log("Current user:", currentUser);
    useUser.set(prevUser => ({ ...prevUser, name: 'Alice Johnson' }));
  };

  return <button onClick={handleClick}>Update User</button>;
}