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Discussion on: 1 line of code: How to remove all duplicates from an Array

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Michael Currin

Also worth adding that you might want to stop once you have a set and not convert it back to an array.

Why?

Lookup time from a set is constant to check if a value is in a set while in an array of 1000 elements worst case you have to go through 1000 elements until you find the one at the end.

Secondly when you convert from array to set, the order will be lost. Sets are inherently unordered. So when you convert from set to array you will not get the order of the original array. So you might as well keep the set.

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qm3ster profile image
Mihail Malo

It's actually specced to preserve insertion order: developer.mozilla.org/en-US/docs/W...

(...spread operator calls y[Symbol.iterator], which is specced to be the same as what is returned by .values() on Set)

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Michael Currin

Oh interesting, in Python it is unordered.