Inside Keeping Components Pure you will find a topic Side Effects: (un)intended consequences, in the first example where it shows component that break this rule , the output produce by given example is not correct it return
Tea cup for guest #1
Tea cup for guest #2
Tea cup for guest #3 not
Tea cup for guest #2
Tea cup for guest #4
Tea cup for guest #6
Inside Keeping Components Pure you will find a topic Side Effects: (un)intended consequences, in the first example where it shows component that break this rule , the output produce by given example is not correct it return Tea cup for guest #1 Tea cup for guest #2 Tea cup for guest #3 not Tea cup for guest #2 Tea cup for guest #4 Tea cup for guest #6