useContext or similar global shared state system

i’ve seen a few mention on it in the different Pr/issues but can’t find anything about it in the current fre package. Is it still something that is planned? A Pr was also talking about a fre/compat for context. Is this a future plan or already there(couldn’t find it)?

[yisar]

Because of the upgrade of new version fre2, this work was not performed, but this is what we will do in the future.

Shared state may be easy with hooks API, for example:

export const createContext = defaultValue => {
  const context = {
    value: defaultValue,
    subs: new Set(),
    Provider: function Provider({ value, children }) {
      useLayout(() => {
        context.subs.forEach(fn => fn(value))
        context.value = value
      })
      return children
    }
  }
  return context
}

export const useContext = (context, selector) => {
  const subs = context.subs
  const [, forceUpdate] = useReducer(c => c + 1, 0)
  const selected = selector ? selector(context.value) : context.value
  const ref = useRef(null)
  useEffect(() => {
    ref.current = selected
  })
  useEffect(() => {
    const fn = nextValue => {
      if (ref.current === selector(nextValue)) return
      forceUpdate()
    }
    subs.add(fn)
    return () => subs.delete(fn)
  }, [subs])
  return selected
}

const Context = createContext({ count1: 0, count2: 1 })

function App(){
  const context = useContext(Context, ctx => ctx.count1) // selector
...
}

After fre2 is finally released, we can add some api and compat packages, it will be soon.

[yisar]

@mindplay-dk I don’t want to use pub-sub in the core code of fre (just like preact). If I have to, I prefer to set shoudComponentUpdate for all components, and then use pub-sub similar technologies