004.1 Index as a key is an anti-pattern

[pvienneau]

May be outside the scope of your learning modules, but thought I'd drop this here in case you were interested.

https://medium.com/@robinpokorny/index-as-a-key-is-an-anti-pattern-e0349aece318#.9wchkw5td

It would be bad practise to use a mapping function's index as the keys to the generation of multiple children, as it may cause unexpected results when the data source would get updated, especially on the addition/removal of items. The fix would be to use some kind of id would within the data source that makes each item unique, though I understand that this may be outside the scope of your learning modules as you're surely trying to show the fundamentals of React.