Recoil: use setTimeout in selector (set)

[Changsik00]

i try to two times set in selector (set)

first normal set
second delay set

but delay set not work
set(loadingState, {timeout: null, checkCount: 0})

import {atom, selector} from 'recoil'

const LOADING_MAX_TIME = 5000

const loadingState = atom({
    key: 'loadingState',
    default: {
        checkCount: 0,
        timeout: null,
    },
})

const showLoadingSelect = selector({
    key: 'showLoadingSelect',
    set: ({set}) => {
        set(loadingState, (prevState) => {
            if (prevState.timeout) {
                clearTimeout(prevState.timeout)
            }
            const timeout = setTimeout(() => {
                // set is not work !!!!
                set(loadingState, {timeout: null, checkCount: 0})
            }, LOADING_MAX_TIME)

            return {
                checkCount: prevState.checkCount + 1,
                timeout,
            }
        })
    },
})

const hideLoadingSelect = selector({
    key: 'hideLoadingSelect',
    set: ({set}) => {
        set(loadingState, (prevState) => ({
            ...prevState,
            checkCount: prevState.checkCount - 1,
        }))
    },
})

const isLoadingSelect = selector({
    key: 'isLoadingSelect',
    get: ({get}) => {
        const state = get(loadingState)
        return state.checkCount > 0
    },
})

export {showLoadingSelect, hideLoadingSelect, isLoadingSelect}
export default loadingState

[BenjaBobs]

This seems like something that's a better fit for useRecoilCallback.

[drarmstr]

Thanks @BenjaBobs! Yup, async sets are not allowed for selector set() method. useRecoilCallback() is the proper tool for this usecase.

Note the discussion in #762 for a feature request for async selector set, but the possible semantics for that might be for an async transaction and wouldn't apply to setTimeout().