How to remove duplicates from a javascript array

Ever wondered about the different ways you can remove duplicates from a JavaScript array?

This short article shows a few methods and compares how they perform when provided with arrays of different sizes.

Small arrays

Arrays containing 25 integers.

Medium arrays

Arrays containing 40 thousand integers.

Larger arrays

Arrays containing 4 million integers.

Tiny arrays

Arrays containing 4 integers.

Conclusion

• Performance wise the clear winner is Regular for loop with object key.
• In terms of conciseness and readability, Spread set is my favorite.
• Not suprisingly Filter with indexOf performs well with tiny arrays, where it’s O(n²) is not an issue.
• SurpirsinglySpread set was 76% slower for larger arrays, even though it was the second best. I would have thought it would be the most optimized solution.