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Removes all duplicates from an array in place.


First install using npm:

npm install uniq

Then use it as follows:

var arr = [1, 1, 2, 2, 3, 5]
//  1,2,3,5 

require("uniq")(array[, compare, sorted])

Removes all duplicates from a sorted array in place.

  • array is the array to remove items from
  • compare is an optional comparison function that returns 0 when two items are equal, and something non-zero when they are different. If unspecified, then the default equals will be used.
  • sorted if true, then assume array is already sorted

Returns: A reference to array

Time Complexity: O(array.length * log(arra.length)) or O(array.length) if sorted

Why use this instead of underscore.uniq[ue]?

A few reasons:

  • This library updates the array in place without making an extra copy (and so it is faster for large arrays)
  • It also accepts a custom comparison function so you can remove duplicates from arrays containing object
  • It is more modular in the sense that it doesn't come with a bazillion other utility grab bag functions.


(c) 2013 Mikola Lysenko. MIT License