javascript - Understanding of Delete operator in JS - 


var trees = ["redwood", "bay", "cedar", "oak", "maple"];  delete trees[3];    if (3 in trees) {    console.log(trees[3]);  }  else {    console.log("not found");  }

the answer shows "not found" not display undefined. why that? , @ end, when count length of array shows, 5 , not 4. why that? please explain examples.

the answer shows "not found" not display undefined. why that?

you deleted property named 3 (this not same property existing having value undefined). since not exist, not in array. hit else branch.

and @ end, when count length of array shows, 5 , not 4

the length name of highest property named after integer, plus one.


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