Getting this error: Method “key” is only meant to be run on a single node. 0 found instead

[RadekKosiada]

@Marmiz

usersOnline.map((item, index) => {
return <li key={index}>{item}</li>
})

I have the same issue as @glitton
Your solution, @besschua98, works in my local host but doest work on fCC.
I get this error: Method “key” is only meant to be run on a single node. 0 found instead.

[RadekKosiada]

Thanks @camperextraordinaire. My issue concerned only the variable renderOnline and so to deal with it I tried two approaches,
1.

const renderOnline = usersOnline.map((user, index) => { <li key={index}>{user}</li> })

this is solution from the previous challenge and gives the error and doesn’t work on my local host.

const renderOnline = usersOnline.map(x => <li key={x.username}>{x.username}</li>)

Now, when I tried again, it passed the test, but I wouldn’t come up with if it wasn’t for @besschua98

[jeffdx.mathew]

@RadekKosiada

const renderOnline = usersOnline.map(x =>

{x.username}

)

I am getting the same error.

[jeffdx.mathew]

@RadekKosiada

const renderOnline = usersOnline.map((user, index) => {

{user}

})

I understood the reason. I have made some changes in the state values. Thts why.