Advertisements Does anyone what the code inside the onChange is doing? I understand that …textData is the spread operator, but why is it spreaded inside of a { } and what is [e.target.name]: e.target.value doing, is this a new javascript syntax? Sorry for noob question! setTextData({ …textData, [e.target.name]: e.target.value }) The rest of the file… Read More Does anyone know what this line of Javascript code is doing in React?

Advertisements Here is my notification component. Notification.js const Notification = (props) => { const [dNone, setdNone] = useState(false); useEffect(() => { const timeout = setTimeout(() => { setdNone(true); }, 4000); return () => { clearTimeout(timeout); }; }, []); return ( // type // 1 : error-alert // 2 : warning-alert // 3 : info-alert //… Read More setTimeout not working properly if i pass key prop to maped element

Advertisements I have an output from my return Object like the below: { "note_1": 14, "note_2": 0, "note_3": 5, "note_4": 17, "note_5": 22 } I need to transform this into a new Array where i would need to add values from the above into new keys like the below structure and order reversed [ {note:… Read More Transform Object to array with new keys in reactJs

Advertisements In my example below, why is there an infinite loop of errors in the devtools console? It seems like resetErrorBoundary() is causing useEffect to trigger again and vice versa leading to an infinite loop, but I don’t understand why useEffect would keep running even with a constant value in its dependency array. This answer… Read More Infinite loop in useEffect with constant dependency array using react-error-boundary

Advertisements Im developing my portfolio and a problem just appearin (the error message in Title). i have an array with the data of my projects, that im mapping with some functions to change the style of the cards of the projects. i dont know whats happen. that error message is apearing in this line: <div… Read More Cannot read properties of undefined (reading 'id'). React Js

Advertisements I am passing a prop from the parent component, but inside the child component, the prop is not accessible. Please see the return statement of the parent component where I have passed the card as a prop. import {useState } from ‘react’; // importing styles import ‘./styles/Card.css’ // importing components import Card from ‘./components/Card’… Read More A prop is not accessible inside the child component even after passing it in the parent component

Advertisements I have this small project I wrote in javascript and I’m trying to rewrite it using React. I have an Alert section where I prepend a message to so it appears at the top of the list, then gets removed after 5 seconds. HTML: <div id="alert-container"> <button onclick="addAlert(‘alert’)">Add</button> </div> JS: function addAlert(message) { const… Read More Transitioning from JS to React: How can I prepend an element and then remove it after some time?

Advertisements I have an handlechange function const [values, SetValues] = useState({ addrId: "", addrType: "", addrLine1: "", addrLine2: "", countryId: "", stateId: "", countyId: "", zip: "", }); const handleChange = (e) => { const { name, value } = e.target; SetValues({ …values, [name]: value, }); }; I tried to update some field(countryID) using other… Read More Update a array out side handlechange function React JS

Advertisements I have array with objects like [{id: 123, isTrue: true}]. The array I get with props in my component. And in it I have to change isTrue when my component mount. I use useState and useEffect: const [myArray, setMyArray] = useState([]); useEffect(() => { setMyArray(arrFromProps.map((item) => { item.isTrue = false; })); }, []); And… Read More Change object`s value in useState

Advertisements I am trying to upload some files using ReactJS, but I want my UI to only have a single "Upload" button instead of two "choose file" and "upload" button. Here is the code: import React, { useRef } from ‘react’; import Button from ‘@mui/material/Button’; function Filesubmit() { const fileInput = useRef(null); async function handleSubmit(event)… Read More Replacing "choose file" and "upload" button with single button