Map function ignores empty items

[thiagomata]

$ node -v
Version: v9.8.0
$ uname -a
Platform: Linux thiagomata 4.13.0-36-generic #40~16.04.1-Ubuntu SMP Fri Feb 16 23:25:58 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

$ node

    var data = [];
    data[3] = 3;
    data[5] = 5;
    console.log( data.length); // 6
    console.log( data.map( x => 1 ) );

Expected:
[ 1, 1, 1, 1, 1, 1]

Result:
[ <3 empty items>, 1, <1 empty item>, 1 ]

https://repl.it/@thiagodamata/MapIngoresEmptyItems

[cjihrig]

Array.prototype.map() skips holes, but still has corresponding elements in the result. Node doesn't provide the implementation, so I'll close this issue, since there is nothing to be done here.

[vsemozhetbyt]

@thiagomata
More detailed info: http://exploringjs.com/es6/ch_arrays.html#_array-operations-and-holes