Removing Array Duplicates In ES6

Photo by Jessica Felicio on Unsplash

Here are 4 ways to remove duplicates from an array and return only the unique values.

1. Set

Set is one of the cool thing happening in ES6. It’s a new data structure that stores unique values of any type. You can iterate through the elements of a set in insertion order. A value in the Set may only occur once; it is unique in the Set’s collection.

2. Filter

The filter() method creates a new array with all elements that pass the test implemented by the provided function.

- Bonus: Retrieve the duplicate values

3. Reduce

In order to find out this option, let’s understand what these two methods are doing: reduce and includes.


The reduce() method executes a reducer function (that you provide) on each member of the array resulting in single output value.


The includes() method determines whether an array includes a certain value among its entries, returning true or false as appropriate.

4. lodash

Do not forget: The bundle size for lodash@4.17.11 is 24.2kB (minified + gzipped). See here.



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