use-state-proxy

Using Proxy API to auto dispatch React.useState(). Inspired from @State() in @stencil/core.

Installation

## using npm
npm install use-state-proxy

## or using yarn
yarn add use-state-proxy

## or using pnpm
pnpm install use-state-proxy

Typescript Signature

export function useStateProxy<T extends object>(initialValue: T): T;

Comparison

With use-state-proxy

You can get/set the values, and call mutating methods (e.g. array.push()) directly.

The 'setState' action is auto dispatched when the value is changed, which auto trigger re-rendering.

Usage Example:

import React from 'react'
import { useStateProxy } from 'use-state-proxy'

function DemoUseStateProxy() {
  let state = useStateProxy({
    text: '',
    list: ['init']
  })
  return <>
    <input
      value={state.text}
      onChange={e => state.text = e.target.value}
    />
    <button onClick={() => [state.list.push(state.text), state.text = '']}>
      Save
    </button>
    <ul>
      {state.list.map((item, i) => <li key={i}>
        <button onClick={() => state.list.splice(i, 1)}>Delete</button>
        <span>{item}</span>
      </li>)}
    </ul>
  </>
}

export default DemoUseStateProxy

Using useStateProxy(), the array can be updated with state.list.push(state.text) and state.list.splice(i, 1) directly. This invokes proxied methods, and it will auto trigger re-rendering.

Without use-state-proxy

You need to set up the states one-by-one, and explicitly call the setHooks to trigger re-rendering.

Moreover, there is syntax noise when updating complex data type, e.g. Array, Map, Set, and Object.

import React, { useState } from 'react'

function DemoUseState() {
  let [text, setText] = useState('')
  let [list, setList] = useState(['init'])
  return <>
    <input value={text} onChange={e => setText(e.target.value)} />
    <button onClick={() => [setList([...list, text]), setText('')]}>
      Save
    </button>
    <ul>
      {list.map((item, i) => <li key={i}>
        <button onClick={() => setList(list.filter((_, j) => i !== j))}>
          Delete
        </button>
        <span>{item}</span>
      </li>)}
    </ul>
  </>
}

export default DemoUseState

In this example, in order to 'push' an item to the list, it manually destructs the original array with spread syntax ... then append the new item at the end.

Also, to remove an item from the list, it constructs a new array with list.filter(), involving multiple levels of array indices, which is error-prone.

The same hurdles applies to object as well. And it get worse when it comes to Set* and Map**.

*: To update a Set, we can run setList(new Set([...list, item]))

**: To update a Map, we can run setList(new Map([...list, [key, value]]))

Features

• Auto trigger re-render when invoking mutating methods on state fields
  • Array
  • Map
  • Set
  • Date
  • Object
• Create a variant for shared state, as simpler alternative to redux store (using redux or context)
• Refactor to use create-react-library structure

License

BSD-2-Clause (Free Open Source Software)