Develop Reference

Trigger useEffect with anotherComponents

I have 2 components, the Favorites component, makes a request to the api and maps the data to Card.
I also have a BtnFav button, which receives an individual item, and renders a full or empty heart according to a boolean.
Clicking on the BtnFav render removes a certain item from the favorites database.
What I need is that in the Favorites component, when I click on the BtnFavs component, the useEffect of Favorites is triggered again to bring the updated favorites.
How can i solve this? I have partially solved it with a global context(favoritesUser), but is there any other neater alternative?
The data flow for now would be something like this:
Favorites component fetches all the complete data and passes it to the Card component, the Card component passes individual data to the BtnFavs component.
Favorites Component:
const fetchWines = async () => {
try {
const vinos = await axios.get(`/api/favoritos/${id}`);
const arrVinos = vinos.data.map((vino) => {
return vino.product;
});
setVinosFavs(arrVinos);
} catch (err) {
console.error(err);
}
};
useEffect(() => {
fetchWines();
}, [favoritesUser]);
return (
<div>
<h1>Mis favoritos</h1>
<Card listWines={vinosFavs} />
</div>
);
BtnFavs:
const handleClickFav = (e) => {
if (!boton) {
axios.post("/api/favoritos/add", { userId, productId }).then((data) => {
setBoton(true);
return;
});
}
axios.put("/api/favoritos/delete ", { userId, productId }).then((data) => {
setBoton(false);
setFavoritesUser(data);
});
};
What I need is that in the Favorites component, when I click on the BtnFavs component, the useEffect of Favorites is triggered again to bring the updated favorites.
How can i solve this? I have partially solved it with a global context(favoritesUser), but is there any other neater alternative?

The pattern you want is called a callback function, just like the onClick of a button. You pass a function to your components that get executed given a condition. If you want fetchWines to be called again, then just pass the function in as a prop.
Favorites Component:
<Card listWines={vinosFavs} refresh={fetchWines} />
Card Component
<BtnFavs onDelete={refresh} ... />
BtnFavs Component
onDelete();
You can name it whatever you want, but generally callbacks will be named like on<condition>.
If you really wanted useEffect to be triggered then you would pass a setState function that set one of the dependencies, but I don't see a point in this case.

I will share code, because this problem its normal for me, i really want to learn and improve that.
const Favorites = () => {
const { favoritesUser } = useFavoritesContext();
const user = useSelector((state) => state.user);
const id = user.id;
const [vinosFavs, setVinosFavs] = useState([]);
const fetchWines = async () => {
try {
const vinos = await axios.get(`/api/favoritos/${id}`);
const arrVinos = vinos.data.map((vino) => {
return vino.product;
});
setVinosFavs(arrVinos);
} catch (err) {
console.error(err);
}
};
useEffect(() => {
fetchWines();
}, [favoritesUser]);
return (
<div>
<h1>My favorits</h1>
<Grid listVinos={vinosFavs} />
</div>
);
};
export default Favorites
Grid
export default function Grid({ listVinos }) {
return (
<div>
<ul className={styles.layoutDeVinos}>
{listVinos?.map((element) => {
return <WineCard key={element.id} vino={element} />;
})}
</ul>
</div>
);
}
Card
export default function WineCard({ vino }) {
return (
<>
<div>
<Link to={`/products/${vino.id}`}>
<li>
<div className={styles.card}>
<div
className={styles.img1}
style={{
backgroundImage: `url(${vino.images})`,
}}
></div>
<div className={styles.text}>{vino.descripcion}</div>
<div className={styles.catagory}>
{vino.nombre}
<i className="fas fa-film"></i>
</div>
<div className={styles.views}>
{vino.bodega}
<i className="far fa-eye"></i>{" "}
</div>
</div>
</li>
</Link>
<div className="botonesUsuario">
<BtnFavs vino={vino} />
</div>
</div>
</>
);
}
BTN FAVS
export default function BtnFavs({ vino }) {
const { setFavoritesUser } = useFavoritesContext();
const [boton, setBoton] = useState(false);
const user = useSelector((state) => state.user);
const userId = user.id;
const productId = vino.id;
useEffect(() => {
axios
.post("/api/favoritos/verify", { userId, productId })
.then((bool) => setBoton(bool.data));
}, []);
const handleClickFav = (e) => {
if (!boton) {
axios.post("/api/favoritos/add", { userId, productId }).then((data) => {
setBoton(true);
return;
});
}
axios.put("/api/favoritos/delete ", { userId, productId }).then((data) => {
setBoton(false);
setFavoritesUser(data);
});
};
return (
<>
{!user.id ? (
<div></div>
) : boton ? (
<span
class="favIcons material-symbols-rounded"
onClick={handleClickFav}
>
favorite
</span>
) : (
<span className="material-symbols-rounded" onClick={handleClickFav}>
favorite
</span>
)}
</>
);
}

Component data was gone after re rendering, even though Component was react.memo already

I have two components.
First is called: BucketTabs
Second is called:BucketForms
To have a better idea. Below pictures illustrate it.
When I switching tab, different form will be showed below.
Q: Whenever I switch from one tab to other tab, and then switch back, the content in the previous BucketForms will be gone. But, gone data are supposed to be stored into a state of that BucketForms.
In fact, I've memo the BucketForms already, so I've expected the content(data) would not be gone.
What's the problem and how could I prevent the data to be gone after switching tab.
My BucketTabs:
import { BucketForms } from '~components/BucketForms/BuckForms'
export const BucketTabs: React.FC = () => {
const items = useMemo<ContentTabsItem[]>((): ContentTabsItem[] => {
return [
{
title: '1',
renderContent: () => <BucketForms key="1" bucketCategory="1" />,
},
{
title: '2',
renderContent: () => <BucketForms key="2" bucketCategory="2" />,
},
]
}, [])
return (
<div className="row">
<div className="col">
<ContentTabs items={tabs} kind="tabs" />
</div>
</div>
)
}
BucketForms
function PropsAreEqual(prev, next) {
const result = prev.bucketCategory === next.bucketCategory;
return result;
}
interface IData {
portfolioValue?: number
}
export const BucketForms: React.FC<IProps> = React.memo(props => {
const { bucketCategory } = props
const [data, setData] = useState<IData>({
})
const view = ({
portfolioValue,
}: IData) => {
return (
<>
<div className="row portfolio">
<FormNumericInput
key="input-portfolio-value"
name="portfolioValue"
required
value={portfolioValue}
/>
</div>
</>
)
}
return (
<Form
onChange={e => {
setData({ ...data, ...e, })
}}
>
{view(data)}
</Form>
)
}, PropsAreEqual)

How to keep already chosen value in ReactJS

I have following code.
What I'm trying to do is, in the first step, select one of the elements, store it in my state, and in the last step, console.log all my data. Also, the user can go from the last step to the first and change what he chose before. But the problem is that I can't save what the user selects for the first time.
For example, if the user selects the second one, and then on the last step they go back, then the first one is displayed as selected. How can I fix this?
here is my code
App.js
const [current, setCurrent] = useState(0);
const [data, setData] = useState({
firstName: "AAA",
lastName: "BBB",
age: 26
});
const steps = [
{
content: (
<PackageChoose setCurrent={setCurrent} data={data} setData={setData} />
),
id: 0
},
{
content: <LastStep setCurrent={setCurrent} data={data} />,
id: 1
}
];
return (
<div className="App">
<div>{steps[current].content}</div>
</div>
);
packageChoose (or first step)
const PackageChoose = ({ setCurrent, data, setData }) => {
const [selected, setSelected] = useState(1);
const [packageType, setPackageType] = useState(data.package || "choice");
return (
<div>
<div
onClick={() => {
setPackageType("choice");
setData({ ...data, packageType: packageType });
}}
>
<SelectCard
id={1}
selected={selected}
onSelect={setSelected}
text="text 1"
/>
</div>
<div
onClick={() => {
setPackageType("select");
setData({ ...data, packageType: packageType });
}}
>
<SelectCard
id={2}
selected={selected}
onSelect={setSelected}
text="text 2"
/>
</div>
<button onClick={() => setCurrent(1)}>Next</button>
</div>
);
};
Last step
const LastStep = ({ setCurrent, data }) => {
return (
<div>
LastStep
<button
onClick={() => {
setCurrent(0);
}}
>
Previous
</button>
<button onClick={() => console.log("data===>", data)}> submit </button>
</div>
);
};
Selected Card reusable component
const SelectCard = ({ id, selected, onSelect, text }) => {
const myClassName =
id === selected
? Styles.selectCardWrapperActives
: Styles.selectCardWrapper;
return (
<div className={classNames(myClassName)} onClick={() => onSelect(id)}>
<div> {text} </div>
</div>
);
};
Please help me to fix this problem.

You can move the selected state in PackageChoose to App level.
In App.js define the selected state and pass as props.
export default function App() {
const [selected, setSelected] = useState(1);
...
...
<PackageChoose
...
...
selected={selected}
setSelected={setSelected}
/>
}
In PackageChoose use the props passed above and remove the local selected state.
const PackageChoose = ({ setCurrent, data, setData, setSelected, selected }) => {

You need to update the packageType inside onClick handler. Since setState calls are batched and enqueued inside event handler and state updates may be asynchronous. You can't access the packageType state immediately after setting it.
PackageChoose.js
Card 1
onClick={() => setData({ ...data, packageType: "choice" })}
Card 2
onClick={() => setData({ ...data, packageType: "select" })}
set the packageType directly on data.

Why onclick function isn't rendering (React.js)?

I’m working on building an e-commerce website in React. In which, there will be a navigation bar with all the categories and once a user clicked on a specific category, it will render all the products that belongs to the checked category in the same page. In the project I have two .js files which are NavBar.js where it contains all the stuff for the navigation bar and AllItems.js where all products are rendered.
My problem now, is that onclick in NavBar.js doesn't render AllItems.js. It works with console.log("sss") but it doesn't work with <AllItems/>
Here is my code in NavBar.js
function NavBar() {
const [allCategories, setAllCategories] = useState([])
const [currency, setCurrency] = useState([])
useEffect(() => {
fetchAnyQuery(
`
query{
categories{
name
}
}
`).then(data => {
setAllCategories( data.data.categories )
})
},[])
// for currency options
useEffect(() => {
fetchAnyQuery(`
query{
currencies
}
`
).then(data => {
setCurrency(data.data.currencies)
})
},[])
return (
<nav id = "NavBar">
<div id="NavBar-content">
<div className = "leftSide" id = "leftNav">
{allCategories.map((allCategories, index) => {
if (index == 0){
// return a checked tab
return(
<>
<input className='radio-category' id={allCategories.name} type='radio' name="nav" onClick={
function (){
console.log("ssss");
<AllItems/>
}
} checked/>
<label htmlFor={allCategories.name} className='category-label'><h5 className="tab-text">{allCategories.name.toUpperCase()}</h5></label>
</>
)
}
else {
// return unchecked tab
return(
<>
<input className='radio-category' id={allCategories.name} type='radio' name="nav" onClick={ function (){changeCategoryState(allCategories.name); <AllItems/>} } />
<label htmlFor={allCategories.name} className='category-label'><h5 className="tab-text">{allCategories.name.toUpperCase()}</h5></label>
</>
)
}
})}
</div>
<div className = "centerSide">
{/*<a href="/">*/}
{/* /!*<img src={logo} />*!/*/}
{/* Logo*/}
{/*</a>*/}
<button onClick={function (){ console.log(getCategoryState()) }}>
Abo Kalb
</button>
</div>
<div className = "rightSide">
<select className="currencySelector" id="currencySelector">
{currency.map((currency, index) =>{
return(
<option value={ JSON.stringify(currency.indexOf(index)) } > {getSymbolFromCurrency(currency.toString()) + " " + currency.toString()} </option>
)
})}
</select>
</div>
</div>
</nav>
);
}
export default NavBar;
Also, here is my code for AllItems.js file:
function AllItems() {
// The state that I want to use in NavBar.js
// const [category, setCategory] = useState([getCategoryState()])
const [products, setProducts] = useState([])
useEffect(() => {
fetchAnyQuery(
`
query{
categories{
name
products{
name
id
}
}
}
`
).then(data => {
// Here I'm trying to do all the required stuff
// console.log(category)
})
},[])
console.log("All Items RENDERED!!")
return (
<>
<h1>{ getCategoryState() }</h1>
<div className="itemContainer" id="itemContainer">
</div>
</>
)
}
export default AllItems;

From what I understood, you want to render different categories' data based on which category is clicked, but you can not call a component on the click, that's not how React works. Instead set a state and render the component conditionally according to the state value, and set the state when the component needs to be rendered.
Assuming that you're fetching your items from a server, you will have to store that data in a state
const [allItems, setAllTems] = useState([])
Then add a state that will help you render your items conditionally
const [showAllItems, setShowAllItems] = useState(false)
In your JSX, use && to render your data when the state gets all the data
<> {showAllItems && <AllItems>} </>
if you're having troubles understanding how this works, I suggest you checking React documentations, it explains very well how you can manipulate the state

Use a parent component to manage the state. When you update the radio input in Nav update the state, and then filter the data based on that selection.
const { useState } = React;
function Example({ data }) {
const [ items, setItems ] = useState(data);
const [ selection, setSelection ] = useState('');
// When you click a button, set the selection state
function handleClick(e) {
setSelection(e.target.dataset.type);
}
// `filter` out the items you want to display
// based on the selection
function filteredItems() {
return items.filter(item => item.type === selection);
}
return (
<div>
<Nav>
Dairy: <input onClick={handleClick} type="radio" data-type="dairy" name="food" />
Meat: <input onClick={handleClick} type="radio" data-type="meat" name="food" />
Vegetable: <input onClick={handleClick} type="radio" data-type="vegetable" name="food" />
</Nav>
<Items items={filteredItems()} />
</div>
);
};
// `map` over the filtered data
function Items({ items }) {
return items.map(item => <div>{item.name}</div>);
}
function Nav({ children }) {
return children;
}
const data = [
{ name: 'cow', type: 'meat' },
{ name: 'bree', type: 'dairy' },
{ name: 'chicken', type: 'meat' },
{ name: 'sprout', type: 'vegetable' }
];
ReactDOM.render(
<Example data={data} />,
document.getElementById('react')
);
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/17.0.2/umd/react.production.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/17.0.2/umd/react-dom.production.min.js"></script>
<div id="react"></div>

How to add HTML element onClick in React with a useState object array?

I am fetching random users from an API and putting them in a useState object array, this works as I checked in console. The issue is I want to display a new user on button click but it doesn't work, however if I write the same JSX code outside of an onClick, it works, let me demonstrate:
This doesn't work
const addUser = () => {
object.map((item) => {
return (
<div>
<h1>{item.firstName}</h1>
<h1>{item.age}</h1>
<h1>{item.gender}</h1>
<img src={item.img} alt="" />
</div>
)
})
}
return (
<div className="App">
<button onClick={addUser}
>+</button>
</div>
);
This works:
return (
<div className="App">
{object.map((item) => {
return (
<div>
<h1>{item.firstName}</h1>
<h1>{item.age}</h1>
<h1>{item.gender}</h1>
<img src={item.img} alt="" />
</div>
)
})}
</div>
);
Here is the full code if it matters:
function App() {
const URL = "https://randomuser.me/api/"
const [object, setObject] = useState([{ firstName: 'jon', age: 20, gender: 'male', img: 'none' }])
useEffect(() => {
fetch(URL)
.then(res => res.json())
.then(data => {
const result = data.results[0]
const obj = {
firstName: result.name.first,
age: result.dob.age,
gender: result.gender,
img: result.picture.large
}
setObject(prevData => prevData.concat(obj))
})
}, [])
const addUser = () => {
object.map((item) => {
return (
<div>
<h1>{firstName}</h1>
<h1>{item.age}</h1>
<h1>{item.gender}</h1>
<img src={item.img} alt="" />
</div>
)
})
}
console.log(object[0])
console.log(object[1])
return (
<div className="App">
<button onClick={() => addUser}
>+</button>
</div>
);
}
export default App;

Two problems with your code are
You are expecting a button onClick function to return DOM elements and somehow render them in your app.
If you really want to show users only when the button is clicked, you
can set a flag that turns true when clicked on the button and then
show users list, returning DOM elements on button onClick won't
render them.
Not wrapping addUser in return.
const addUser = () => {
return (
// existing code
)
}
For code, you can check here