What this snippet does
Set is the fastest way to deduplicate an array and perform union, intersection, and difference operations.
Expected output
[ 1, 2, 3, 4 ] [ 1, 2, 3, 4, 5 ] [ 3, 4 ] [ 1, 2, 1 ]
Why practise typing this
Typing set 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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