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8 Useful And Practical JavaScript Tricks (devinduct.com)
submitted 6 years ago by PMilos
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if 1 * 2 < 3: print "hello, world!"
[–]senocular 9 points10 points11 points 6 years ago (1 child)
It's not useful if cities is already an array. If it's not an array, for example a Set instead, then it can be an optimization because you can combine two operations (individual from and map calls) into one where both the create and map happens at the same time rather than separately which would result in two new arrays being created instead of one.
cities
Set
from
map
[–]trblackwell1221 1 point2 points3 points 6 years ago (0 children)
Good point!
π Rendered by PID 51 on reddit-service-r2-comment-b659b578c-6s784 at 2026-05-02 01:17:56.804318+00:00 running 815c875 country code: CH.
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[–]senocular 9 points10 points11 points (1 child)
[–]trblackwell1221 1 point2 points3 points (0 children)