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JavaScript React by Example Refining the App Filter Bug

Posted by Thomas Gauperaa
Thomas Gauperaa
3,584 Points

"Filter bug" chapter in "React by example"

Can't the bug be solved by using indexOf like this?

handleConfirmation={() => props.toggleConfirmationAt(props.guests.indexOf(guest))}

It'll then find the index the current guest (in map) has in the guest's array in state and use that index to toggle the confirmation?

1 Answer

Tosin Jemilehin
Tosin Jemilehin
3,663 Points

Hi Thomas,

Your code will still execute but in reality, you'd probably be iterating over a list of entries queried from a database, at this point, it is expedient you use the id property as it has more integrity than using index.

Moreover, using indexOf will make your iterate over the array in (n*2) times, which implies that, the execution time will be high and its a lot of work considering system memory, imagine you'r dealing with over 10k element array.

I hope this helps.

Cheers

Thomas Gauperaa
Thomas Gauperaa
3,584 Points

Thank you, Tosin, that makes sense :)

Tosin Jemilehin
Tosin Jemilehin
3,663 Points

You welcome.