I know about key prop, so i made it in listitem component
const ListItem = ({item}) => {
const {result, time, id} = item;
return(
<li key={id} className='list__item'>
<span className='item__result'>{result} cps</span>
<span className='item__date'>{time}</span>
<button className='item__delete'>delete</button>
</li>
)}
And here is component, where I use it
const Leadboard = () => {
const [data, setData] = useState([{result:'5,63', time:'08.06.2022', id: (new Date()).toString(16)}, {result:'5,63', time:'08.06.2022', id: +(new Date() - 1)}, {result:'5,63', time:'08.06.2022', id: +(new Date() - 2)}]);
let elements=data.map(item => {
return (
<>
<ListItem item={item} />
</>
)
});
return(
<div className='app-leadboard'>
<span className='app-leadboard__title'>Your's best results:</span>
<ol className='app-leadboard__list' type='1'>
{elements}
</ol>
</div>
)}
But after render I still see "key prop" error
I spent so much time on this, but can't understand what's wrong. So smb, help pls with it
You’ve got the wrong list. It’s the <ListItem> components that need the key. (And you can get rid of the react fragments around them because they are pointless).
React first accesses the empty bracket (<> </> ) before accessing the key attribute in your child component.
So you need to either
key attribute to it// Use React.Fragment
let elements=data.map(item => { return
(
<React.Fragment key={item.id}>
<ListItem item={item} />
</React.Fragment>
)
});
and remove the key in the child (ListItem) component
ListItem.js
<li
/* Remove this
key={id}
*/
className='list__item'>
OR
Get rid of the empty brackets (<> </>) and reference the child's component directly.
let elements=data.map(item => {
return (<ListItem item={item} />)
});
and leave the key attribute in the child component
More on React Fragment. React Official Docs