Cross-component, persistable useState() effect, without context

Why?

Even with the advent of React hooks, cross-component shared state is still being solved with either context/provider hooks (messy), or traditional stores like redux/mobx (messier). This store more or less mirrors the signature of the incredibly elegant useState() hook, with optional local persistence built-in.

API

useStore(namespace, [initialValue=undefined], [options={}])

returns [ value, setValue ] pair, identical to useState() in React

import useStore from 'use-store'
// note: import { useStore } from 'use-store' will continue to work

// must be called inside a React component
let [ value, setValue ] = useStore('foo')
// value = undefined
setValue(3)
// value = 3

Arguments

• namespace (string) required - this is the reference you'll share throughout the app for a specific value. E.g. useStore('myValue')
• initialValue (anything) optional - optional default value which will be set by the first component that encounters this hook on a given namespace. This will be ignored if persist is enabled and value found locally.
• options (object) optional - options for the hook (see below):
  • persist (boolean, default=false)

globalStore.set(namespace, initialValue, options) // params identical to useStore() above

For manually setting initial values and persist options so individual components don't have to (also to solve race conditions)

import { globalStore } from 'use-store'

globalStore.set('foo', 'bar', { persist: true })

Example (Elaborate)

  // ComponentA.js

  import React from 'react'
  import useStore from 'use-store'

  export default function ComponentA() {
    let [ value, setValue ] = useStore('myValue', 3)

    return (
      <div>
        ComponentA:value = { value }

        <button onClick={() => setValue(value + 1)}>
          Increment
        </button>
      </div>
    )
  }

  // ComponentB.js

  import React from 'react'
  import useStore from 'use-store'
  import ComponentA from './ComponentA'

  export default function ComponentB() {
    let [ value, setValue ] = useStore('myValue', 3)

    return (
      <div>
        ComponentB:value = { value } // this will increment as ComponentA clicks are registered

        <ComponentA />
      </div>
    )
  }

Example (Event Handlers)

  import React from 'react'
  import useStore from 'use-store'

  export default function ComponentA() {
    let [ value, setValue ] = useStore('myValue', 3)

    // traditional event handler no longer needed for inputs
    const changeHandler = (e) => setValue(e.target.value)

    return (
      <div>
        <!-- this still works -->
        <input value={value} onChange={changeHandler} />

        <!-- but so does this (no need to wrap the setter in an event handler) -->
        <input value={value} onChange={setValue} />
      </div>
    )
  }