I am using the below code to create a simple to-do list. Everything works fine except the async-storage components since the tasks are either not being saved or not being fetched. Could anyone kindly point out any modifications I can do to the useEffects to fix this issue?
/* eslint-disable prettier/prettier */
import React, {useState, useEffect} from 'react';
import {View, StyleSheet, FlatList, Alert} from 'react-native';
import AsyncStorage from '@react-native-async-storage/async-storage';
import uuid from 'react-native-uuid';
import Header from './components/header.js';
import Task from './components/task.js';
import Add from './components/add.js';
const App = () => {
const [tasks, setTasks] = useState([]);
const addTask = (text) => {
if (!text) {
Alert.alert(null,'No task entered\nPlease enter a task',);
} else {
setTasks(prevState => {
return [...prevState, {id: uuid.v4(), title: text}];
});
}
};
const removeTask = (id) => {
setTasks(prevState =>{
return prevState.filter(task => task.id!=id);
});
};
useEffect(() => {
const saveTasks = async () => {
await AsyncStorage.setItem('TASKS', JSON.stringify(tasks));
}
saveTasks();
}, [tasks]);
useEffect(() => {
const fetchTasks = async () =>{
const saved = await AsyncStorage.getItem('TASKS');
setTasks(JSON.parse(saved));
}
fetchTasks();
}, []);
return (
<View style={styles.container}>
<Header/>
<Add addTask={addTask} />
<FlatList
data={tasks}
renderItem={({ item }) => <Task text={item.title} removeTask={removeTask} id={item.id}/>}
keyExtractor={task => task.id}
/>
</View>
);
};
const styles = StyleSheet.create({
container: {
flex: 1,
},
});
export default App;
The problem is caused by the below useEffect. It saves tasks in storage every time tasks changes, but also on first render where tasks is equal to [], the value given to useState.
useEffect(() => {
const saveTasks = async () => {
await AsyncStorage.setItem('TASKS', JSON.stringify(tasks));
}
saveTasks();
}, [tasks]);
An easy way to solve this issue is to remove the above useEffect, and change addTask and removeTask as follow:
const addTask = (text) => {
if (!text) {
Alert.alert(null,'No task entered\nPlease enter a task',);
} else {
const newTasks = [...tasks, {id: uuid.v4(), title: text}];
await AsyncStorage.setItem('TASKS', JSON.stringify(newTasks));
setTasks(newTasks);
}
};
const removeTask = (id) => {
const newTasks = tasks.filter(task => task.id!=id);
await AsyncStorage.setItem('TASKS', JSON.stringify(newTasks));
setTasks(newTasks);
};