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REACT Duplicated Key Warning

I am currently get this duplicated key warning "Warning: Encountered two children with the same key". However, I am unsure where this duplication of key comes from. I am using the fileData id as my key which should be unique as it is firebase generated id. Therefore, I am not so sure what is happening behind here.
Here are my codes below and the warning I get.
MultimediaDetails.js
import React, { useEffect, useState } from "react";
import * as AiIcons from "react-icons/ai";
import * as FaIcons from "react-icons/fa";
import { database } from "../../../firebase";
import ViewImageFileModal from "../../modals/multimediaModals/view/ViewImageFileModal";
/**
* It's a component that displays audio, video, and image files
* #param props - The props object that is passed to the component.
* #returns The MultimediaDetails component is being returned.
*/
const MultimediaDetails = (props) => {
/* Destructuring the props object. */
const { pId } = props;
/* Setting the state of the component. */
const [imageData, setImageData] = useState([]);
const [imageMessage, setImageMessage] = useState(true);
const userType = JSON.parse(localStorage.getItem("admin") ?? false);
// Modal Variables
const [showViewImageModal, setShowViewImageModal] = useState(false);
const [fileData, setFileData] = useState(Object);
/**
* When the user clicks on the audio, video, or image file, the file data is set and the modal is
* toggled.
* #param obj
*/
const viewImageFile = (obj) => {
setFileData(obj);
toggleViewImageModal();
};
/* The function to toggle modal states */
const toggleAddImageModal = () => setShowAddImageModal((p) => !p);
const toggleViewImageModal = () => setShowViewImageModal((p) => !p);
useEffect(() => {
/* Query data from database and listening for changes. */
const imageQuery = database.portfolioRef.doc(pId).collection("images");
const unsubscribeImage = imageQuery.onSnapshot((snapshot) => {
if (snapshot.docs.length !== 0) {
setImageMessage(false);
setImageData(
snapshot.docs.map((doc) => ({ ...doc.data(), id: doc.id }))
);
} else {
setImageMessage(true);
}
});
return () => {
unsubscribeImage();
};
}, [pId]);
return (
<div className="multimedia-section">
<div id="image-section">
<div id="image-header">
<h6>
<u>Images</u>
</h6>
{userType ? (
<button className="addbtn" onClick={() => toggleAddImageModal()}>
<AiIcons.AiOutlinePlus /> Add Image File
</button>
) : (
<></>
)}
</div>
<div id="image-content" className="multimedia-flex">
{imageMessage ? (
<p>There is not existing images for this portfolio.</p>
) : (
<div>
{imageData.map((doc) => (
<button
key={doc.id}
className="fileBtn"
onClick={() => viewImageFile(doc)}
>
<FaIcons.FaImage /> {doc.imageName}
</button>
))}
</div>
)}
</div>
</div>
<ViewImageFileModal
show={showViewImageModal}
toggleModal={toggleViewImageModal}
pId={pId}
data={fileData}
key={fileData.id}
/>
</div>
);
};
export default MultimediaDetails;
The initialised values for the Modal.
/* Setting the initial state of the component. */
const valueState = {
name: '',
description: ''
}
const { currentUser } = useAuth();
const [formStateDisabled, setFormStateDisabled] = useState(true);
const [deleteState, setDeleteState] = useState(false);
const [message, setMessage] = useState('');
const [imageUrl, setImageUrl] = useState("");
const [loadForm, setLoadForm] = useState(false)
const [view, setView] = useState(false);
/* Destructuring the props object. */
const { show, toggleModal } = props;
const { handleChange, handleSubmit, values, errors, loading } =
useForm(validateUpdate, valueState, handleUpdate);
useEffect(() => {
if (Object.keys(props.data).length !== 0) {
values.name = props.data.imageName;
values.description = props.data.imageDesc;
setLoadForm(true);
}
}, [])
The warning I get (Shown Below), each time I click on the modal button to open the button, I noticed the warning actually repeats twice, and when I close it, it repeats another 2 times making it 4. I am not sure what is the cause of this, please help! Thank you!
Updates of trials
I only have 4 rows of data, all of which has its own unique id. Therefore I am unsure of where the duplicated key came from. However, if I remove the modal key "fileData.id" this warning would disappear. However, my component state will not reset and there will be a lot of props data issue that would surface. Where data for the previously clicked button will appear on the another button. Or the data might not appear at all.
FOR ADDITIONAL INFORMATION:
This is the output for the map buttons
I don't see any duplicates, and I am not sure where the issue is. Is there something I am doing wrong to cause this error. I checked my DB there isn't any data error as well.

Recommended solution
The problem is that your doc.id is repeating.
You are setting the imageData at the imageQuery.onSnapshot callback function, when you run the following code:
setImageData(snapshot.docs.map((doc) => ({ ...doc.data(), id: doc.id })));
What you need to make sure is that doc.id is unique in this context (because you're using this value at the key attribute in your buttons).
That's the correct way to fix it.
Alternative solution
Another way to handle it (as a last resort), is using the following code, where you use the index position of the element at the key attribute:
{imageData.map((doc, index) => (
<button
key={index}
className="fileBtn"
onClick={() => viewImageFile(doc)}
>
<FaIcons.FaImage /> {doc.imageName}
</button>
))}
But this is not recommended according to the React documentation:
We don’t recommend using indexes for keys if the order of items may
change. This can negatively impact performance and may cause issues
with component state. Check out Robin Pokorny’s article for an
in-depth explanation on the negative impacts of using an index as a key.
If you choose not to assign an explicit key to list items then
React will default to using indexes as keys.
Here is an in-depth explanation about why keys are necessary if you’re
interested in learning more.

Instead of doc.id use map item index like bellow. See if it works.
{imageData.map((index, doc) => (
<button
key={index}
className="fileBtn"
onClick={() => viewImageFile(doc)}>
<FaIcons.FaImage /> {doc.imageName}
</button>
))}

This is the culprit:
{imageData.map((doc) => (
<button
key={doc.id}
className="fileBtn"
onClick={() => viewImageFile(doc)}
>
<FaIcons.FaImage /> {doc.imageName}
</button>
))}
The main issue here is that doc.id is duplicate, probably you have duplicate data in your imageData or ou have a faulty data in your database or something that generate a non-unique id.
To easily fix the issue, what you can do is use index of map.
{imageData.map((doc, index) => (
<button
key={index}
className="fileBtn"
onClick={() => viewImageFile(doc)}
>
<FaIcons.FaImage /> {doc.imageName}
</button>
))}
index are always unique. but I suggest you should fix and see why you have duplicate data instead of just bypassing it with an index.
UPDATE
This is quite a hacky solution, but since I can't really pin point what's causing the issue without investigating first hand, let's make it so you don't have to pass a key on the modal.
So instead of storing the object data on the state, store the id instead:
Rename fileData to fileDataId.
const [fileDataId, setFileDataId] = useState(0);
then store the id when clicking the button.
{imageData.map((doc) => (
<button
key={doc.id}
className="fileBtn"
onClick={() => viewImageFile(doc.id)}
>
<FaIcons.FaImage /> {doc.imageName}
</button>
))}
on the Modal, you have to pass the imageData and the selected id, then remove the key:
<ViewImageFileModal
show={showViewImageModal}
toggleModal={toggleViewImageModal}
pId={pId}
list={imageData}
selectedId={fileDataId}
/>
then inside ViewImageFileModal you can declare data as:
const data= props.list.find(image => image.id === props.selectedId);

I just wrap my model with a condition if imageId exist and it works already!
{imageId !== '' &&
<ViewImageFileModal
show={showViewImageModal}
toggleModal={toggleViewImageModal}
imageData={imageData}
key={imageId}
/>
}

How to avoid using useSelector hook many times?

I am having a trouble with decoupling business logic and ui. I am new to react. I know that my component contains too much responsibilities. Also i am not sure if it is a good idea to use a lot of variables with useSelector hook, but i dont know hot to avoid it. Please can someone explain how to fix it or give some adviсe what should to read/watch?
const Catalog = () => {
const dispatch = useDispatch();
const items = useSelector(state => state.catalog.plantsList);
const isFetching = useSelector(state => state.catalog.isFetching);
const currentPage = useSelector(state => state.catalog.currentPage);
const totalCount = useSelector(state => state.catalog.totalCount);
const limitItems = useSelector(state => state.catalog.limitItems);
const pagesCount = Math.ceil(totalCount/limitItems);
const pages = [];
createPages(pages, pagesCount, currentPage);
useEffect(() => {
dispatch(fetchData(currentPage, limitItems));
}, [currentPage]);
let plantItems = items.map(p => <PlantItem key={p.id} id={p.id} image={p.image} name={p.name}
cost={p.cost}/>)
return (
<div className={s.catalog}>
<p className={s.catalog__description}>Сдавая пластик в пункты приема, Вы получаете природные баллы. За один
килограмм пластика можно получить
10 природных баллов.</p>
<div className={ isFetching === false ? s.catalog__list : s.fetching }>
{
isFetching === false ?
plantItems
:
<Preloader/>
}
</div>
<div className={s.catalog__pages}>
{pages.map((page, index) => <div
key={index}
className={currentPage == page ? s.currentPage : s.page}
onClick={() => dispatch(setCurrentPage(page))}>{page}</div>)}
</div>
</div>
);
};

Looking at your example, you can use de-structure property. Something like this:
const {
plantsList: items,
isFetching,
currentPage,
totalCount,
limitItems
} = useSelector(state => state.catalog);

You should definitely not do what the other answers here suggest: useSelector(state => state.catalog) will update your component whenever state.catalog.anythingUnrelated updates, even if you only need state.catalog.a, state.catalog.b and state.catalog.c in your component.
You would be oversubscribing and your app would be rerendering a lot more often than necessary.
Always selectively subscribe to the data you actually need. Calling useSelector a few more times is totally fine and generally more performant than oversubscribing. (we even recommend doing that in the style guide)
As an alternative, you can also move calculation of important data from the component into the selector and create a memoized selector. That will not be a lot less code, but it will move it out of the component. Read Deriving Data with Selectors on that.
Or you use a non-memoized selector in combination with a custom comparison function, like this:
const {
plantsList: items,
isFetching,
currentPage,
totalCount,
limitItems
} = useSelector(({catalog}) => ({
plantsList: catalog.plantsList,
isFetching: catalog.isFetching,
currentPage: catalog.currentPage,
totalCount: catalog.totalCount,
limitItems: catalog.limitItems
}), shallowEqual);
but as you see that's not a lot less code either.
In the end: it's just fine to have multiple useSelector calls.

Creating like button for multiple items

I am new to React and trying to learn more by creating projects. I made an API call to display some images to the page and I would like to create a like button/icon for each image that changes to red when clicked. However, when I click one button all of the icons change to red. I believe this may be related to the way I have set up my state, but can't seem to figure out how to target each item individually. Any insight would be much appreciated.
`
//store api data
const [eventsData, setEventsData] = useState([]);
//state for like button
const [isLiked, setIsLiked] = useState(false);
useEffect(() => {
axios({
url: "https://app.ticketmaster.com/discovery/v2/events",
params: {
city: userInput,
countryCode: "ca",
},
})
.then((response) => {
setEventsData(response.data._embedded.events);
})
.catch((error) => {
console.log(error)
});
});
//here i've tried to filter and target each item and when i
console.log(event) it does render the clicked item, however all the icons
change to red at the same time
const handleLikeEvent = (id) => {
eventsData.filter((event) => {
if (event.id === id) {
setIsLiked(!isLiked);
}
});
};
return (
{eventsData.map((event) => {
return (
<div key={event.id}>
<img src={event.images[0].url} alt={event.name}></img>
<FontAwesomeIcon
icon={faHeart}
className={isLiked ? "redIcon" : "regularIcon"}
onClick={() => handleLikeEvent(event.id)}
/>
</div>
)
`

Store likes as array of ids
const [eventsData, setEventsData] = useState([]);
const [likes, setLikes] = useState([]);
const handleLikeEvent = (id) => {
setLikes(likes.concat(id));
};
return (
<>
{eventsData.map((event) => {
return (
<div key={event.id}>
<img src={event.images[0].url} alt={event.name}></img>
<FontAwesomeIcon
icon={faHeart}
className={likes.includes(event.id) ? "redIcon" : "regularIcon"}
onClick={() => handleLikeEvent(event.id)}
/>
</div>
);
})}
</>
);

Your issue is with your state, isLiked is just a boolean true or false, it has no way to tell the difference between button 1, or button 2 and so on, so you need a way to change the css property for an individual button, you can find one such implementation by looking Siva's answer, where you store their ids in an array

Reactj.s: Item deleted only after refresh | Delete Method

I'm trying to send a delete request to delete an item from an API.
The API request is fine when clicking on the button. But Item get's deleted only after refreshing the browser!
I'm not too sure if I should add any parameter to SetHamsterDeleted for it to work?
This is what my code looks like.
import React, {useState} from "react";
const Hamster = (props) => {
const [hamsterDeleted, setHamsterDeleted] = useState("")
async function deleteHamster(id) {
const response = await fetch(`/hamsters/${id}`, { method: "DELETE" });
setHamsterDeleted()
}
return (
<div>
<p className={props.hamster ? "" : "hide"}>
{hamsterDeleted}
</p>
<button onClick={() => deleteHamster(props.hamster.id)}>Delete</button>
<h2>{props.hamster.name}</h2>
<p>Ålder:{props.hamster.age}</p>
<p>Favorit mat:{props.hamster.favFood}</p>
<p>Matcher:{props.hamster.games}</p>
<img src={'./img/' + props.hamster.imgName} alt="hamster"/>
</div>
)
};
export default Hamster;
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.6.3/umd/react.production.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.6.3/umd/react-dom.production.min.js"></script>

Imagine you have a parent component (say HamstersList) that returns/renders list of these Hamster components - it would be preferable to declare that deleteHamster method in it, so it could either: a) pass some prop like hidden into every Hamster or b) refetch list of all Hamsters from the API after one got "deleted" c) remove "deleted" hamster from an array that was stored locally in that parent List component.
But since you are trying to archive this inside of Hamster itself, few changes might help you:
change state line to const [hamsterDeleted, setHamsterDeleted] = useState(false)
call setHamsterDeleted(true) inside of deleteHamster method after awaited fetch.
a small tweak of "conditional rendering" inside of return, to actually render nothing when current Hamster has hamsterDeleted set to true:
return hamsterDeleted ? null : (<div>*all your hamster's content here*</div>)

What do you want to do in the case the hamster is deleted? If you don't want to return anything, you can just return null.
I'm not too sure if I should add any parameter to SetHamsterDeleted for it to work?
Yes, I'd make this a boolean instead. Here's an example:
import React, { useState } from "react";
const Hamster = (props) => {
const [hamsterDeleted, setHamsterDeleted] = useState(false);
async function deleteHamster(id) {
const response = await fetch(`/hamsters/${id}`, { method: "DELETE" });
setHamsterDeleted(true);
}
if (hamsterDeleted) return null;
return (
<div>
<p className={props.hamster ? "" : "hide"}>
{hamsterDeleted}
</p>
<button onClick={() => deleteHamster(props.hamster.id)}>Delete</button>
<h2>{props.hamster.name}</h2>
<p>Ålder:{props.hamster.age}</p>
<p>Favorit mat:{props.hamster.favFood}</p>
<p>Matcher:{props.hamster.games}</p>
<img src={'./img/' + props.hamster.imgName} alt="hamster"/>
</div>
);
};
HOWEVER! Having each individual hamster keep track of its deleted state doesn't sound right (of course I don't know all your requirements but it seems odd). I'm guessing that you've got a parent component which is fetching all the hamsters - that would be a better place to keep track of what has been deleted, and what hasn't. That way, if the hamster is deleted, you could just not render that hamster. Something more like this:
const Hamsters = () => {
const [hamsers, setHamsters] = useState([]);
// Load the hamsters when the component loads
useEffect(() => {
const loadHamsters = async () => {
const { data } = await fetch(`/hamsters`, { method: "GET" });
setHamsters(data);
}
loadHamsters();
}, []);
// Shared handler to delete a hamster
const handleDelete = async (id) => {
await fetch(`/hamsters/${id}`, { method: "DELETE" });
setHamsters(prev => prev.filter(h => h.id !== id));
}
return (
<>
{hamsters.map(hamster => (
<Hamster
key={hamster.id}
hamster={hamster}
onDelete={handleDelete}
/>
))}
</>
);
}
Now you can just make the Hamster component a presentational component that only cares about rendering a hamster, eg:
const Hamster = ({ hamster, onDelete }) => {
const handleDelete = () => onDelete(hamster.id);
return (
<div>
<button onClick={handleDelete}>Delete</button>
<h2>{hamster.name}</h2>
<p>Ålder:{hamster.age}</p>
<p>Favorit mat:{hamster.favFood}</p>
<p>Matcher:{hamster.games}</p>
<img src={'./img/' + hamster.imgName} alt="hamster"/>
</div>
);
};

Add active border to only a single item on click

Clicking on an article I want to add a 'selected' border around it:
const [selected, setSelected] = useState(false);
const handleClick = (evt) => {
setSelected(true)
};
<article
onClick={handleClick}
className={`${selected ? "border-red-500" : ""} ... `}
>
This works great for a single article but how would I go about it if I had multiple articles? I only want to have one selected at a time. This method would obviously add a border around every article when clicked.

If you want to use multiple articles, You can use map to render and setSelected is id/index of article:
const handleClick = (id) => {
setSelected(id !== selected ? id : "")
};
listArticles.map((item, index) => (
<article
key = {item.id} // or index
onClick={() => handleClick(item.id)} //or index
className={`${selected === item.id ? "border-red-500" : ""} ... `} // or index
>
))

This usually looks something like this:
const [selected, setSelected] = useState(false);
list.map((body, i) => <article key={i}
onClick={() => setSelected(i)}
className={`${selected == i ? "border-red-500" : ""} ... `}
>{body}</article>)
But it depends a little on how you store, render, and identify your list of things (in this case articles).