How to check my conditions on react hooks - reactjs

Question

I need check my conditions on react hooks when startup or change value
I try that by this code but I cant run without Btn
import React,{useEffect} from 'react';
import { StyleSheet, View } from 'react-native';
import * as Permissions from 'expo-permissions';
import { Notifications} from 'expo';
export default function NotificationsTest() {
const y = 5;
const askPermissionsAsync = async () => {
await Permissions.askAsync(Permissions.USER_FACING_NOTIFICATIONS);
};
const btnSendNotClicked = async () => {
if(y===5){
await askPermissionsAsync();
Notifications.presentLocalNotificationAsync({
title: "Title",
body: "****** SUBJ *******",
ios:{
sound:true,
},
android:{
sound:true,
color:'#512da8',
vibrate:true,
}
});
}else{
} }
useEffect(()=>{
return btnSendNotClicked
}
,[])
return (
<View style={styles.container}>
</View>
);
}
and I just want to confirm is it good practice to checking this kind of condition in useEffect ?

Answer 1

Hi on startup useEffect with empty array will be fired and this will be happened during the page load (first time), so you can write your condition there. here is an example:
useEffect(()=> {
// Your condition here
}, []);
If you have a variable like value then you can write another useEffect like below and set that variable (value) in second parameter of useEffect as an array
const [value, setValue] = useState('');
useEffect(()=> {
// Your condition here
}, [value]);

Answer 2

const y = 5;
//this one will run every time the component renders
//so you could use it to check for anything on the startup
useEffect(()=> {
// Your condition here
}, []);
Otherwise you could add a value or array of values that you want to track for changes so this useEffect bellow Will only run if the y const changes so you could add an if check there to check if y===5 also this useEffect will run on the first initial of the const y so its perfect in your case
}
useEffect(()=> {
// will run every time y const change and on the first initial of y
if (y === 5)
{
//do your stuff here
}
}, [y]);