What this snippet does
map always returns a new array of the same length — the original is never modified.
Expected output
[ 2, 4, 6, 8, 10 ]
[ 'item_1', 'item_2', 'item_3', 'item_4', 'item_5' ]
[ { id: 1, value: 1 }, ... ]Why practise typing this
Typing arrays code builds muscle memory for the symbols and indentation JavaScript uses most, which prose-based typing tests never cover. DevType measures your words per minute and accuracy on this snippet and tracks the individual characters you mistype, so later lessons can target them.
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