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Cover image for 🚀 Quick tips! 3 ways to get unique values from an array. 💜
Niall Maher
Niall Maher

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🚀 Quick tips! 3 ways to get unique values from an array. 💜

#javascript #webdev #programming #tutorial

In this super short article, learn how to create 3 different functions that return all of the unique values in an array.

You can watch the video version here or keep scrolling for the code snippets.

1) Filter the values 👇 

const getUniqueValues = array => (
  array.filter((currentValue, index, arr) => arr.indexOf(currentValue) === index)
);
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2) Using reduce 👇 

const getUniqueValues = array => array.reduce(
  (accumulator, currentValue) => (
    accumulator.includes(currentValue) ? accumulator : [...accumulator, currentValue]
  ), []
);
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3) Destructure a new Set 👇 

const getUniqueValues = array => [...new Set(array)];
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Top comments (5)

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crs1138 profile image
Honza •

It seems that the [... new Set(arr)] is way faster than the other two.

jsbench.me/xnkapa5nxq/1

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patarapolw profile image
Pacharapol Withayasakpunt • • Edited

Set also reliably keep what is .add() first as well. But I never really tested [...new Set(arr)] on whether the sequence is kept.

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nialljoemaher profile image
Niall Maher •

That's actually great to know too. Finally, my laziness is paying off. 😂

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crs1138 profile image
Honza •

HA! Exactly my thought on this topic 😂

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dailydevtips1 profile image
Chris Bongers •

Set is such a impressive and easy way to do this, love to use it <3