UseState hook not updating the step properly - reactjs

Question

I want to change state value with change in the 'select' element. So I am calling the setFilter method in the onChange handler. But state is not getting updated. It's holding the previous value.
How to fix this issue?
I want to change state value with change in the 'select' element. So I am calling the setFilter method in the onChange handler. But state is not getting updated. It's holding the previous value.
How to fix this issue?
import React, { useState, useEffect } from 'react'
import { useHistory } from 'react-router-dom'
import { useApolloClient} from 'react-apollo';
import { Formik, Form, ErrorMessage } from 'formik';
import * as Yup from "yup";
import AsyncPaginate from 'react-select-async-paginate'
import { GET_ITEM_CODES } from '../../library/Query';
export default function SampleForm({initialData}){
const history = useHistory();
const [productFilter, setProductFilter] = useState('');
const client = useApolloClient();
const defaultAdditional = {
cursor : null
}
const shouldLoadMore = (scrollHeight, clientHeight, scrollTop) => {
const bottomBorder = (scrollHeight - clientHeight) / 2
return bottomBorder < scrollTop
}
const loadItemcodeOptions = async (q = 0, prevOptions, {cursor}) => {
console.log('qu',q*1)
const options = [];
console.log('load')
const response = await client.query({
query:GET_ITEM_CODES,
variables : {filter: {
number_gte : q*1
},skip:0, first:4, after: cursor}
})
console.log('res',response)
response.data.itemCodes.itemCodes.map(item => {
return options.push({
value: item.number,
label: `${item.number} ${item.description}`
})
})
console.log('0',options)
return {
options,
hasMore: response.data.itemCodes.hasMore,
additional: {
cursor: response.data.itemCodes.cursor.toString()
}
}
}
const handleFilter = (e) => {
console.log('e',e)
setProductFilter(e.value)
console.log('pf',productFilter) // output is previous State(wrong)
}
useEffect(() => {
console.log('epf',productFilter) // output the current state(expected)
})
return(
<Formik
initialValues = {{
itemCode: !!initialData ? {value: initialData.itemCode, label: initialData.itemCode} : '',
}}
validationSchema = {Yup.object().shape({
itemCode: Yup.number().required('Required'),
})}
>
{({values, isSubmitting, setFieldValue, touched, errors }) => (
<Form>
<label htmlFor="itemCode">Item Code</label>
<AsyncPaginate
name="itemCode"
defaultOptions
debounceTimeout={300}
cacheOptions
additional={defaultAdditional}
value={values.itemCode}
loadOptions={loadItemcodeOptions}
onChange={option => {
handleFilter(option)
setFieldValue('itemCode', option)
}}
shouldLoadMore={shouldLoadMore}
/>
<ErrorMessage name="itemcode"/>
<pre>{JSON.stringify(values, null, 2)}</pre>
</Form>
)}
</Formik>
)
}

Answer 1

Actually setProductFilter is setting state asynchronously, so you'll get updated state in the effect, not right after calling setState. But your effect is going to run every time when your component gets re-rendered so you should add productFilter as a dependency of useEffect.
One other thing I want to mention is, I don't know about your use case but you should stick to the rule: Single source of truth. You have two states for productFilter, one is in Formik, i.e. itemCode, and other in your local state. I think you can remove your local state and use item code from formikProps.values.itemCode.