@rehooks/local-storage
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React hook for enabling synchronization with local-storage.
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API Docs can be found here.
Table of Contents
Features
- Automatic JSON serialization
- Synchronization across multiple tabs
- Provides functions for updating the localStorage and triggering a state update outside of the component
- Type hinting via TypeScript
Install
With Yarn
yarn add @rehooks/local-storage
With NPM
npm i @rehooks/local-storage --save
Usage
Write to Storage
This can be anywhere from within your application.
Note: Objects that are passed to writeStorage are automatically stringified.
This will not work for circular structures.
import React from 'react';
import { writeStorage } from '@rehooks/local-storage';
let counter = 0;
const MyButton = () => (
<button onClick={_ => writeStorage('i', ++counter)}>
Click Me
</button>
);
Read From Storage
This component will receive updates to itself from local storage.
Javascript:
import React from 'react';
import { useLocalStorage } from '@rehooks/local-storage';
function MyComponent() {
const [counterValue] = useLocalStorage('i');
return (
<div>
<h1>{counterValue}</h1>
</div>
);
}
Typescript:
import React from 'react';
import { useLocalStorage } from '@rehooks/local-storage';
function MyComponent() {
const [counterValue] = useLocalStorage<number>('i');
return (
<div>
<h1>{counterValue}</h1>
</div>
);
}
Optionally use a default value
Note: Objects that are passed to useLocalStorage's default parameter will be automatically
stringified. This will not work for circular structures.
import React from 'react';
import { useLocalStorage } from '@rehooks/local-storage';
function MyComponent() {
const [user] = useLocalStorage('user', { name: 'Anakin Skywalker' });
return (
<div>
<h1>{user.name}</h1>
</div>
);
}
Delete From Storage
You may also delete items from the local storage as well.
import { writeStorage, deleteFromStorage } from '@rehooks/local-storage';
writeStorage('name', 'Homer Simpson');
deleteFromStorage('name');
const thisIsNull = localStorage.getItem('name');
Using With Context
It is advisable to use this hook with context if you want to have a properly
synchronized default value. Using useLocalStorage
in two different components
with the same key but different default values can lead to unexpected behaviour.
Using Context will also prevent components from rendering and setting
default values to the localStorage when you just want them to be deleted from localStorage
(assuming the context provider also does not re-render).
import React, { createContext, useContext } from 'react';
import { useLocalStorage } from '@rehooks/local-storage';
const defaultProfile = { name: 'Spongekebob' };
const defaultContextValue = [defaultProfile, () => {}, () => {}];
const ProfileContext = createContext(defaultContextValue);
export const ProfileProvider = ({ children }) => {
const ctxValue = useLocalStorage('profile', defaultProfile);
return (
<ProfileContext.Provider value={ctxValue}>
{children}
</ProfileContext.Provider>
);
};
const useProfile = () => useContext(ProfileContext);
const App = () => {
const [profile] = useProfile();
return <h1>{profile && profile.name}</h1>;
};
export default () => {
return (
<ProfileProvider>
<App />
</ProfileProvider>
);
};
Full Example
You may view this example here on StackBlitz.
Note: The writeStorage and deleteFromStorage functions are provided from useLocalStorage as well,
and do not require you to specify the key when using them.
import React, { Fragment } from 'react';
import { render } from 'react-dom';
import { writeStorage, deleteFromStorage, useLocalStorage } from '@rehooks/local-storage';
const startingNum = 0;
const Clicker = () => (
<Fragment>
<h4>Clicker</h4>
<button onClick={_ => {
writeStorage('num', localStorage.getItem('num')
? +(localStorage.getItem('num')) + 1
: startingNum
)
}}>
Increment From Outside
</button>
<button onClick={_ => deleteFromStorage('num')}>
Delete From Outside
</button>
</Fragment>
);
const IncrememterWithButtons = () => {
const [number, setNum, deleteNum] = useLocalStorage('num');
return (
<Fragment>
<p>{typeof(number) === 'number' ? number : 'Try incrementing the number!'}</p>
<button onClick={_ => setNum(number !== null ? +(number) + 1 : startingNum)}>Increment</button>
<button onClick={deleteNum}>Delete</button>
</Fragment>
);
};
const App = () => (
<Fragment>
<h1> Demo </h1>
<IncrememterWithButtons />
<Clicker />
</Fragment>
);
render(<App />, document.getElementById('root'));
Contributors ✨
Thanks goes to these wonderful people (emoji key):
This project follows the all-contributors specification. Contributions of any kind welcome!